mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 14:06:40 +07:00
280d7a1ede
Pull x86 fpu updates from Ingo Molnar: "The main changes relate to fixes between (lack of) CPUID and FPU detection that should only affect old or weird CPUs, by Andy Lutomirski" * 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/fpu: Fix the "Giving up, no FPU found" test x86/fpu: Fix CPUID-less FPU detection x86/fpu: Fix "x86/fpu: Legacy x87 FPU detected" message x86/cpu: Re-apply forced caps every time CPU caps are re-read x86/cpu: Factor out application of forced CPU caps x86/cpu: Add X86_FEATURE_CPUID x86/fpu/xstate: Move XSAVES state init to a function
1083 lines
28 KiB
C
1083 lines
28 KiB
C
/*
|
|
* xsave/xrstor support.
|
|
*
|
|
* Author: Suresh Siddha <suresh.b.siddha@intel.com>
|
|
*/
|
|
#include <linux/compat.h>
|
|
#include <linux/cpu.h>
|
|
#include <linux/mman.h>
|
|
#include <linux/pkeys.h>
|
|
|
|
#include <asm/fpu/api.h>
|
|
#include <asm/fpu/internal.h>
|
|
#include <asm/fpu/signal.h>
|
|
#include <asm/fpu/regset.h>
|
|
#include <asm/fpu/xstate.h>
|
|
|
|
#include <asm/tlbflush.h>
|
|
|
|
/*
|
|
* Although we spell it out in here, the Processor Trace
|
|
* xfeature is completely unused. We use other mechanisms
|
|
* to save/restore PT state in Linux.
|
|
*/
|
|
static const char *xfeature_names[] =
|
|
{
|
|
"x87 floating point registers" ,
|
|
"SSE registers" ,
|
|
"AVX registers" ,
|
|
"MPX bounds registers" ,
|
|
"MPX CSR" ,
|
|
"AVX-512 opmask" ,
|
|
"AVX-512 Hi256" ,
|
|
"AVX-512 ZMM_Hi256" ,
|
|
"Processor Trace (unused)" ,
|
|
"Protection Keys User registers",
|
|
"unknown xstate feature" ,
|
|
};
|
|
|
|
/*
|
|
* Mask of xstate features supported by the CPU and the kernel:
|
|
*/
|
|
u64 xfeatures_mask __read_mostly;
|
|
|
|
static unsigned int xstate_offsets[XFEATURE_MAX] = { [ 0 ... XFEATURE_MAX - 1] = -1};
|
|
static unsigned int xstate_sizes[XFEATURE_MAX] = { [ 0 ... XFEATURE_MAX - 1] = -1};
|
|
static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask)*8];
|
|
|
|
/*
|
|
* The XSAVE area of kernel can be in standard or compacted format;
|
|
* it is always in standard format for user mode. This is the user
|
|
* mode standard format size used for signal and ptrace frames.
|
|
*/
|
|
unsigned int fpu_user_xstate_size;
|
|
|
|
/*
|
|
* Clear all of the X86_FEATURE_* bits that are unavailable
|
|
* when the CPU has no XSAVE support.
|
|
*/
|
|
void fpu__xstate_clear_all_cpu_caps(void)
|
|
{
|
|
setup_clear_cpu_cap(X86_FEATURE_XSAVE);
|
|
setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
|
|
setup_clear_cpu_cap(X86_FEATURE_XSAVEC);
|
|
setup_clear_cpu_cap(X86_FEATURE_XSAVES);
|
|
setup_clear_cpu_cap(X86_FEATURE_AVX);
|
|
setup_clear_cpu_cap(X86_FEATURE_AVX2);
|
|
setup_clear_cpu_cap(X86_FEATURE_AVX512F);
|
|
setup_clear_cpu_cap(X86_FEATURE_AVX512IFMA);
|
|
setup_clear_cpu_cap(X86_FEATURE_AVX512PF);
|
|
setup_clear_cpu_cap(X86_FEATURE_AVX512ER);
|
|
setup_clear_cpu_cap(X86_FEATURE_AVX512CD);
|
|
setup_clear_cpu_cap(X86_FEATURE_AVX512DQ);
|
|
setup_clear_cpu_cap(X86_FEATURE_AVX512BW);
|
|
setup_clear_cpu_cap(X86_FEATURE_AVX512VL);
|
|
setup_clear_cpu_cap(X86_FEATURE_MPX);
|
|
setup_clear_cpu_cap(X86_FEATURE_XGETBV1);
|
|
setup_clear_cpu_cap(X86_FEATURE_AVX512VBMI);
|
|
setup_clear_cpu_cap(X86_FEATURE_PKU);
|
|
setup_clear_cpu_cap(X86_FEATURE_AVX512_4VNNIW);
|
|
setup_clear_cpu_cap(X86_FEATURE_AVX512_4FMAPS);
|
|
setup_clear_cpu_cap(X86_FEATURE_AVX512_VPOPCNTDQ);
|
|
}
|
|
|
|
/*
|
|
* Return whether the system supports a given xfeature.
|
|
*
|
|
* Also return the name of the (most advanced) feature that the caller requested:
|
|
*/
|
|
int cpu_has_xfeatures(u64 xfeatures_needed, const char **feature_name)
|
|
{
|
|
u64 xfeatures_missing = xfeatures_needed & ~xfeatures_mask;
|
|
|
|
if (unlikely(feature_name)) {
|
|
long xfeature_idx, max_idx;
|
|
u64 xfeatures_print;
|
|
/*
|
|
* So we use FLS here to be able to print the most advanced
|
|
* feature that was requested but is missing. So if a driver
|
|
* asks about "XFEATURE_MASK_SSE | XFEATURE_MASK_YMM" we'll print the
|
|
* missing AVX feature - this is the most informative message
|
|
* to users:
|
|
*/
|
|
if (xfeatures_missing)
|
|
xfeatures_print = xfeatures_missing;
|
|
else
|
|
xfeatures_print = xfeatures_needed;
|
|
|
|
xfeature_idx = fls64(xfeatures_print)-1;
|
|
max_idx = ARRAY_SIZE(xfeature_names)-1;
|
|
xfeature_idx = min(xfeature_idx, max_idx);
|
|
|
|
*feature_name = xfeature_names[xfeature_idx];
|
|
}
|
|
|
|
if (xfeatures_missing)
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
EXPORT_SYMBOL_GPL(cpu_has_xfeatures);
|
|
|
|
static int xfeature_is_supervisor(int xfeature_nr)
|
|
{
|
|
/*
|
|
* We currently do not support supervisor states, but if
|
|
* we did, we could find out like this.
|
|
*
|
|
* SDM says: If state component 'i' is a user state component,
|
|
* ECX[0] return 0; if state component i is a supervisor
|
|
* state component, ECX[0] returns 1.
|
|
*/
|
|
u32 eax, ebx, ecx, edx;
|
|
|
|
cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx);
|
|
return !!(ecx & 1);
|
|
}
|
|
|
|
static int xfeature_is_user(int xfeature_nr)
|
|
{
|
|
return !xfeature_is_supervisor(xfeature_nr);
|
|
}
|
|
|
|
/*
|
|
* When executing XSAVEOPT (or other optimized XSAVE instructions), if
|
|
* a processor implementation detects that an FPU state component is still
|
|
* (or is again) in its initialized state, it may clear the corresponding
|
|
* bit in the header.xfeatures field, and can skip the writeout of registers
|
|
* to the corresponding memory layout.
|
|
*
|
|
* This means that when the bit is zero, the state component might still contain
|
|
* some previous - non-initialized register state.
|
|
*
|
|
* Before writing xstate information to user-space we sanitize those components,
|
|
* to always ensure that the memory layout of a feature will be in the init state
|
|
* if the corresponding header bit is zero. This is to ensure that user-space doesn't
|
|
* see some stale state in the memory layout during signal handling, debugging etc.
|
|
*/
|
|
void fpstate_sanitize_xstate(struct fpu *fpu)
|
|
{
|
|
struct fxregs_state *fx = &fpu->state.fxsave;
|
|
int feature_bit;
|
|
u64 xfeatures;
|
|
|
|
if (!use_xsaveopt())
|
|
return;
|
|
|
|
xfeatures = fpu->state.xsave.header.xfeatures;
|
|
|
|
/*
|
|
* None of the feature bits are in init state. So nothing else
|
|
* to do for us, as the memory layout is up to date.
|
|
*/
|
|
if ((xfeatures & xfeatures_mask) == xfeatures_mask)
|
|
return;
|
|
|
|
/*
|
|
* FP is in init state
|
|
*/
|
|
if (!(xfeatures & XFEATURE_MASK_FP)) {
|
|
fx->cwd = 0x37f;
|
|
fx->swd = 0;
|
|
fx->twd = 0;
|
|
fx->fop = 0;
|
|
fx->rip = 0;
|
|
fx->rdp = 0;
|
|
memset(&fx->st_space[0], 0, 128);
|
|
}
|
|
|
|
/*
|
|
* SSE is in init state
|
|
*/
|
|
if (!(xfeatures & XFEATURE_MASK_SSE))
|
|
memset(&fx->xmm_space[0], 0, 256);
|
|
|
|
/*
|
|
* First two features are FPU and SSE, which above we handled
|
|
* in a special way already:
|
|
*/
|
|
feature_bit = 0x2;
|
|
xfeatures = (xfeatures_mask & ~xfeatures) >> 2;
|
|
|
|
/*
|
|
* Update all the remaining memory layouts according to their
|
|
* standard xstate layout, if their header bit is in the init
|
|
* state:
|
|
*/
|
|
while (xfeatures) {
|
|
if (xfeatures & 0x1) {
|
|
int offset = xstate_comp_offsets[feature_bit];
|
|
int size = xstate_sizes[feature_bit];
|
|
|
|
memcpy((void *)fx + offset,
|
|
(void *)&init_fpstate.xsave + offset,
|
|
size);
|
|
}
|
|
|
|
xfeatures >>= 1;
|
|
feature_bit++;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Enable the extended processor state save/restore feature.
|
|
* Called once per CPU onlining.
|
|
*/
|
|
void fpu__init_cpu_xstate(void)
|
|
{
|
|
if (!boot_cpu_has(X86_FEATURE_XSAVE) || !xfeatures_mask)
|
|
return;
|
|
/*
|
|
* Make it clear that XSAVES supervisor states are not yet
|
|
* implemented should anyone expect it to work by changing
|
|
* bits in XFEATURE_MASK_* macros and XCR0.
|
|
*/
|
|
WARN_ONCE((xfeatures_mask & XFEATURE_MASK_SUPERVISOR),
|
|
"x86/fpu: XSAVES supervisor states are not yet implemented.\n");
|
|
|
|
xfeatures_mask &= ~XFEATURE_MASK_SUPERVISOR;
|
|
|
|
cr4_set_bits(X86_CR4_OSXSAVE);
|
|
xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask);
|
|
}
|
|
|
|
/*
|
|
* Note that in the future we will likely need a pair of
|
|
* functions here: one for user xstates and the other for
|
|
* system xstates. For now, they are the same.
|
|
*/
|
|
static int xfeature_enabled(enum xfeature xfeature)
|
|
{
|
|
return !!(xfeatures_mask & (1UL << xfeature));
|
|
}
|
|
|
|
/*
|
|
* Record the offsets and sizes of various xstates contained
|
|
* in the XSAVE state memory layout.
|
|
*/
|
|
static void __init setup_xstate_features(void)
|
|
{
|
|
u32 eax, ebx, ecx, edx, i;
|
|
/* start at the beginnning of the "extended state" */
|
|
unsigned int last_good_offset = offsetof(struct xregs_state,
|
|
extended_state_area);
|
|
/*
|
|
* The FP xstates and SSE xstates are legacy states. They are always
|
|
* in the fixed offsets in the xsave area in either compacted form
|
|
* or standard form.
|
|
*/
|
|
xstate_offsets[0] = 0;
|
|
xstate_sizes[0] = offsetof(struct fxregs_state, xmm_space);
|
|
xstate_offsets[1] = xstate_sizes[0];
|
|
xstate_sizes[1] = FIELD_SIZEOF(struct fxregs_state, xmm_space);
|
|
|
|
for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
|
|
if (!xfeature_enabled(i))
|
|
continue;
|
|
|
|
cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);
|
|
|
|
/*
|
|
* If an xfeature is supervisor state, the offset
|
|
* in EBX is invalid. We leave it to -1.
|
|
*/
|
|
if (xfeature_is_user(i))
|
|
xstate_offsets[i] = ebx;
|
|
|
|
xstate_sizes[i] = eax;
|
|
/*
|
|
* In our xstate size checks, we assume that the
|
|
* highest-numbered xstate feature has the
|
|
* highest offset in the buffer. Ensure it does.
|
|
*/
|
|
WARN_ONCE(last_good_offset > xstate_offsets[i],
|
|
"x86/fpu: misordered xstate at %d\n", last_good_offset);
|
|
last_good_offset = xstate_offsets[i];
|
|
}
|
|
}
|
|
|
|
static void __init print_xstate_feature(u64 xstate_mask)
|
|
{
|
|
const char *feature_name;
|
|
|
|
if (cpu_has_xfeatures(xstate_mask, &feature_name))
|
|
pr_info("x86/fpu: Supporting XSAVE feature 0x%03Lx: '%s'\n", xstate_mask, feature_name);
|
|
}
|
|
|
|
/*
|
|
* Print out all the supported xstate features:
|
|
*/
|
|
static void __init print_xstate_features(void)
|
|
{
|
|
print_xstate_feature(XFEATURE_MASK_FP);
|
|
print_xstate_feature(XFEATURE_MASK_SSE);
|
|
print_xstate_feature(XFEATURE_MASK_YMM);
|
|
print_xstate_feature(XFEATURE_MASK_BNDREGS);
|
|
print_xstate_feature(XFEATURE_MASK_BNDCSR);
|
|
print_xstate_feature(XFEATURE_MASK_OPMASK);
|
|
print_xstate_feature(XFEATURE_MASK_ZMM_Hi256);
|
|
print_xstate_feature(XFEATURE_MASK_Hi16_ZMM);
|
|
print_xstate_feature(XFEATURE_MASK_PKRU);
|
|
}
|
|
|
|
/*
|
|
* This check is important because it is easy to get XSTATE_*
|
|
* confused with XSTATE_BIT_*.
|
|
*/
|
|
#define CHECK_XFEATURE(nr) do { \
|
|
WARN_ON(nr < FIRST_EXTENDED_XFEATURE); \
|
|
WARN_ON(nr >= XFEATURE_MAX); \
|
|
} while (0)
|
|
|
|
/*
|
|
* We could cache this like xstate_size[], but we only use
|
|
* it here, so it would be a waste of space.
|
|
*/
|
|
static int xfeature_is_aligned(int xfeature_nr)
|
|
{
|
|
u32 eax, ebx, ecx, edx;
|
|
|
|
CHECK_XFEATURE(xfeature_nr);
|
|
cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx);
|
|
/*
|
|
* The value returned by ECX[1] indicates the alignment
|
|
* of state component 'i' when the compacted format
|
|
* of the extended region of an XSAVE area is used:
|
|
*/
|
|
return !!(ecx & 2);
|
|
}
|
|
|
|
/*
|
|
* This function sets up offsets and sizes of all extended states in
|
|
* xsave area. This supports both standard format and compacted format
|
|
* of the xsave aread.
|
|
*/
|
|
static void __init setup_xstate_comp(void)
|
|
{
|
|
unsigned int xstate_comp_sizes[sizeof(xfeatures_mask)*8];
|
|
int i;
|
|
|
|
/*
|
|
* The FP xstates and SSE xstates are legacy states. They are always
|
|
* in the fixed offsets in the xsave area in either compacted form
|
|
* or standard form.
|
|
*/
|
|
xstate_comp_offsets[0] = 0;
|
|
xstate_comp_offsets[1] = offsetof(struct fxregs_state, xmm_space);
|
|
|
|
if (!boot_cpu_has(X86_FEATURE_XSAVES)) {
|
|
for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
|
|
if (xfeature_enabled(i)) {
|
|
xstate_comp_offsets[i] = xstate_offsets[i];
|
|
xstate_comp_sizes[i] = xstate_sizes[i];
|
|
}
|
|
}
|
|
return;
|
|
}
|
|
|
|
xstate_comp_offsets[FIRST_EXTENDED_XFEATURE] =
|
|
FXSAVE_SIZE + XSAVE_HDR_SIZE;
|
|
|
|
for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
|
|
if (xfeature_enabled(i))
|
|
xstate_comp_sizes[i] = xstate_sizes[i];
|
|
else
|
|
xstate_comp_sizes[i] = 0;
|
|
|
|
if (i > FIRST_EXTENDED_XFEATURE) {
|
|
xstate_comp_offsets[i] = xstate_comp_offsets[i-1]
|
|
+ xstate_comp_sizes[i-1];
|
|
|
|
if (xfeature_is_aligned(i))
|
|
xstate_comp_offsets[i] =
|
|
ALIGN(xstate_comp_offsets[i], 64);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Print out xstate component offsets and sizes
|
|
*/
|
|
static void __init print_xstate_offset_size(void)
|
|
{
|
|
int i;
|
|
|
|
for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
|
|
if (!xfeature_enabled(i))
|
|
continue;
|
|
pr_info("x86/fpu: xstate_offset[%d]: %4d, xstate_sizes[%d]: %4d\n",
|
|
i, xstate_comp_offsets[i], i, xstate_sizes[i]);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* setup the xstate image representing the init state
|
|
*/
|
|
static void __init setup_init_fpu_buf(void)
|
|
{
|
|
static int on_boot_cpu __initdata = 1;
|
|
|
|
WARN_ON_FPU(!on_boot_cpu);
|
|
on_boot_cpu = 0;
|
|
|
|
if (!boot_cpu_has(X86_FEATURE_XSAVE))
|
|
return;
|
|
|
|
setup_xstate_features();
|
|
print_xstate_features();
|
|
|
|
if (boot_cpu_has(X86_FEATURE_XSAVES))
|
|
init_fpstate.xsave.header.xcomp_bv = (u64)1 << 63 | xfeatures_mask;
|
|
|
|
/*
|
|
* Init all the features state with header.xfeatures being 0x0
|
|
*/
|
|
copy_kernel_to_xregs_booting(&init_fpstate.xsave);
|
|
|
|
/*
|
|
* Dump the init state again. This is to identify the init state
|
|
* of any feature which is not represented by all zero's.
|
|
*/
|
|
copy_xregs_to_kernel_booting(&init_fpstate.xsave);
|
|
}
|
|
|
|
static int xfeature_uncompacted_offset(int xfeature_nr)
|
|
{
|
|
u32 eax, ebx, ecx, edx;
|
|
|
|
/*
|
|
* Only XSAVES supports supervisor states and it uses compacted
|
|
* format. Checking a supervisor state's uncompacted offset is
|
|
* an error.
|
|
*/
|
|
if (XFEATURE_MASK_SUPERVISOR & (1 << xfeature_nr)) {
|
|
WARN_ONCE(1, "No fixed offset for xstate %d\n", xfeature_nr);
|
|
return -1;
|
|
}
|
|
|
|
CHECK_XFEATURE(xfeature_nr);
|
|
cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx);
|
|
return ebx;
|
|
}
|
|
|
|
static int xfeature_size(int xfeature_nr)
|
|
{
|
|
u32 eax, ebx, ecx, edx;
|
|
|
|
CHECK_XFEATURE(xfeature_nr);
|
|
cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx);
|
|
return eax;
|
|
}
|
|
|
|
/*
|
|
* 'XSAVES' implies two different things:
|
|
* 1. saving of supervisor/system state
|
|
* 2. using the compacted format
|
|
*
|
|
* Use this function when dealing with the compacted format so
|
|
* that it is obvious which aspect of 'XSAVES' is being handled
|
|
* by the calling code.
|
|
*/
|
|
int using_compacted_format(void)
|
|
{
|
|
return boot_cpu_has(X86_FEATURE_XSAVES);
|
|
}
|
|
|
|
static void __xstate_dump_leaves(void)
|
|
{
|
|
int i;
|
|
u32 eax, ebx, ecx, edx;
|
|
static int should_dump = 1;
|
|
|
|
if (!should_dump)
|
|
return;
|
|
should_dump = 0;
|
|
/*
|
|
* Dump out a few leaves past the ones that we support
|
|
* just in case there are some goodies up there
|
|
*/
|
|
for (i = 0; i < XFEATURE_MAX + 10; i++) {
|
|
cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);
|
|
pr_warn("CPUID[%02x, %02x]: eax=%08x ebx=%08x ecx=%08x edx=%08x\n",
|
|
XSTATE_CPUID, i, eax, ebx, ecx, edx);
|
|
}
|
|
}
|
|
|
|
#define XSTATE_WARN_ON(x) do { \
|
|
if (WARN_ONCE(x, "XSAVE consistency problem, dumping leaves")) { \
|
|
__xstate_dump_leaves(); \
|
|
} \
|
|
} while (0)
|
|
|
|
#define XCHECK_SZ(sz, nr, nr_macro, __struct) do { \
|
|
if ((nr == nr_macro) && \
|
|
WARN_ONCE(sz != sizeof(__struct), \
|
|
"%s: struct is %zu bytes, cpu state %d bytes\n", \
|
|
__stringify(nr_macro), sizeof(__struct), sz)) { \
|
|
__xstate_dump_leaves(); \
|
|
} \
|
|
} while (0)
|
|
|
|
/*
|
|
* We have a C struct for each 'xstate'. We need to ensure
|
|
* that our software representation matches what the CPU
|
|
* tells us about the state's size.
|
|
*/
|
|
static void check_xstate_against_struct(int nr)
|
|
{
|
|
/*
|
|
* Ask the CPU for the size of the state.
|
|
*/
|
|
int sz = xfeature_size(nr);
|
|
/*
|
|
* Match each CPU state with the corresponding software
|
|
* structure.
|
|
*/
|
|
XCHECK_SZ(sz, nr, XFEATURE_YMM, struct ymmh_struct);
|
|
XCHECK_SZ(sz, nr, XFEATURE_BNDREGS, struct mpx_bndreg_state);
|
|
XCHECK_SZ(sz, nr, XFEATURE_BNDCSR, struct mpx_bndcsr_state);
|
|
XCHECK_SZ(sz, nr, XFEATURE_OPMASK, struct avx_512_opmask_state);
|
|
XCHECK_SZ(sz, nr, XFEATURE_ZMM_Hi256, struct avx_512_zmm_uppers_state);
|
|
XCHECK_SZ(sz, nr, XFEATURE_Hi16_ZMM, struct avx_512_hi16_state);
|
|
XCHECK_SZ(sz, nr, XFEATURE_PKRU, struct pkru_state);
|
|
|
|
/*
|
|
* Make *SURE* to add any feature numbers in below if
|
|
* there are "holes" in the xsave state component
|
|
* numbers.
|
|
*/
|
|
if ((nr < XFEATURE_YMM) ||
|
|
(nr >= XFEATURE_MAX) ||
|
|
(nr == XFEATURE_PT_UNIMPLEMENTED_SO_FAR)) {
|
|
WARN_ONCE(1, "no structure for xstate: %d\n", nr);
|
|
XSTATE_WARN_ON(1);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This essentially double-checks what the cpu told us about
|
|
* how large the XSAVE buffer needs to be. We are recalculating
|
|
* it to be safe.
|
|
*/
|
|
static void do_extra_xstate_size_checks(void)
|
|
{
|
|
int paranoid_xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE;
|
|
int i;
|
|
|
|
for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
|
|
if (!xfeature_enabled(i))
|
|
continue;
|
|
|
|
check_xstate_against_struct(i);
|
|
/*
|
|
* Supervisor state components can be managed only by
|
|
* XSAVES, which is compacted-format only.
|
|
*/
|
|
if (!using_compacted_format())
|
|
XSTATE_WARN_ON(xfeature_is_supervisor(i));
|
|
|
|
/* Align from the end of the previous feature */
|
|
if (xfeature_is_aligned(i))
|
|
paranoid_xstate_size = ALIGN(paranoid_xstate_size, 64);
|
|
/*
|
|
* The offset of a given state in the non-compacted
|
|
* format is given to us in a CPUID leaf. We check
|
|
* them for being ordered (increasing offsets) in
|
|
* setup_xstate_features().
|
|
*/
|
|
if (!using_compacted_format())
|
|
paranoid_xstate_size = xfeature_uncompacted_offset(i);
|
|
/*
|
|
* The compacted-format offset always depends on where
|
|
* the previous state ended.
|
|
*/
|
|
paranoid_xstate_size += xfeature_size(i);
|
|
}
|
|
XSTATE_WARN_ON(paranoid_xstate_size != fpu_kernel_xstate_size);
|
|
}
|
|
|
|
|
|
/*
|
|
* Get total size of enabled xstates in XCR0/xfeatures_mask.
|
|
*
|
|
* Note the SDM's wording here. "sub-function 0" only enumerates
|
|
* the size of the *user* states. If we use it to size a buffer
|
|
* that we use 'XSAVES' on, we could potentially overflow the
|
|
* buffer because 'XSAVES' saves system states too.
|
|
*
|
|
* Note that we do not currently set any bits on IA32_XSS so
|
|
* 'XCR0 | IA32_XSS == XCR0' for now.
|
|
*/
|
|
static unsigned int __init get_xsaves_size(void)
|
|
{
|
|
unsigned int eax, ebx, ecx, edx;
|
|
/*
|
|
* - CPUID function 0DH, sub-function 1:
|
|
* EBX enumerates the size (in bytes) required by
|
|
* the XSAVES instruction for an XSAVE area
|
|
* containing all the state components
|
|
* corresponding to bits currently set in
|
|
* XCR0 | IA32_XSS.
|
|
*/
|
|
cpuid_count(XSTATE_CPUID, 1, &eax, &ebx, &ecx, &edx);
|
|
return ebx;
|
|
}
|
|
|
|
static unsigned int __init get_xsave_size(void)
|
|
{
|
|
unsigned int eax, ebx, ecx, edx;
|
|
/*
|
|
* - CPUID function 0DH, sub-function 0:
|
|
* EBX enumerates the size (in bytes) required by
|
|
* the XSAVE instruction for an XSAVE area
|
|
* containing all the *user* state components
|
|
* corresponding to bits currently set in XCR0.
|
|
*/
|
|
cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
|
|
return ebx;
|
|
}
|
|
|
|
/*
|
|
* Will the runtime-enumerated 'xstate_size' fit in the init
|
|
* task's statically-allocated buffer?
|
|
*/
|
|
static bool is_supported_xstate_size(unsigned int test_xstate_size)
|
|
{
|
|
if (test_xstate_size <= sizeof(union fpregs_state))
|
|
return true;
|
|
|
|
pr_warn("x86/fpu: xstate buffer too small (%zu < %d), disabling xsave\n",
|
|
sizeof(union fpregs_state), test_xstate_size);
|
|
return false;
|
|
}
|
|
|
|
static int init_xstate_size(void)
|
|
{
|
|
/* Recompute the context size for enabled features: */
|
|
unsigned int possible_xstate_size;
|
|
unsigned int xsave_size;
|
|
|
|
xsave_size = get_xsave_size();
|
|
|
|
if (boot_cpu_has(X86_FEATURE_XSAVES))
|
|
possible_xstate_size = get_xsaves_size();
|
|
else
|
|
possible_xstate_size = xsave_size;
|
|
|
|
/* Ensure we have the space to store all enabled: */
|
|
if (!is_supported_xstate_size(possible_xstate_size))
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* The size is OK, we are definitely going to use xsave,
|
|
* make it known to the world that we need more space.
|
|
*/
|
|
fpu_kernel_xstate_size = possible_xstate_size;
|
|
do_extra_xstate_size_checks();
|
|
|
|
/*
|
|
* User space is always in standard format.
|
|
*/
|
|
fpu_user_xstate_size = xsave_size;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* We enabled the XSAVE hardware, but something went wrong and
|
|
* we can not use it. Disable it.
|
|
*/
|
|
static void fpu__init_disable_system_xstate(void)
|
|
{
|
|
xfeatures_mask = 0;
|
|
cr4_clear_bits(X86_CR4_OSXSAVE);
|
|
fpu__xstate_clear_all_cpu_caps();
|
|
}
|
|
|
|
/*
|
|
* Enable and initialize the xsave feature.
|
|
* Called once per system bootup.
|
|
*/
|
|
void __init fpu__init_system_xstate(void)
|
|
{
|
|
unsigned int eax, ebx, ecx, edx;
|
|
static int on_boot_cpu __initdata = 1;
|
|
int err;
|
|
|
|
WARN_ON_FPU(!on_boot_cpu);
|
|
on_boot_cpu = 0;
|
|
|
|
if (!boot_cpu_has(X86_FEATURE_FPU)) {
|
|
pr_info("x86/fpu: No FPU detected\n");
|
|
return;
|
|
}
|
|
|
|
if (!boot_cpu_has(X86_FEATURE_XSAVE)) {
|
|
pr_info("x86/fpu: x87 FPU will use %s\n",
|
|
boot_cpu_has(X86_FEATURE_FXSR) ? "FXSAVE" : "FSAVE");
|
|
return;
|
|
}
|
|
|
|
if (boot_cpu_data.cpuid_level < XSTATE_CPUID) {
|
|
WARN_ON_FPU(1);
|
|
return;
|
|
}
|
|
|
|
cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
|
|
xfeatures_mask = eax + ((u64)edx << 32);
|
|
|
|
if ((xfeatures_mask & XFEATURE_MASK_FPSSE) != XFEATURE_MASK_FPSSE) {
|
|
/*
|
|
* This indicates that something really unexpected happened
|
|
* with the enumeration. Disable XSAVE and try to continue
|
|
* booting without it. This is too early to BUG().
|
|
*/
|
|
pr_err("x86/fpu: FP/SSE not present amongst the CPU's xstate features: 0x%llx.\n", xfeatures_mask);
|
|
goto out_disable;
|
|
}
|
|
|
|
xfeatures_mask &= fpu__get_supported_xfeatures_mask();
|
|
|
|
/* Enable xstate instructions to be able to continue with initialization: */
|
|
fpu__init_cpu_xstate();
|
|
err = init_xstate_size();
|
|
if (err)
|
|
goto out_disable;
|
|
|
|
/*
|
|
* Update info used for ptrace frames; use standard-format size and no
|
|
* supervisor xstates:
|
|
*/
|
|
update_regset_xstate_info(fpu_user_xstate_size, xfeatures_mask & ~XFEATURE_MASK_SUPERVISOR);
|
|
|
|
fpu__init_prepare_fx_sw_frame();
|
|
setup_init_fpu_buf();
|
|
setup_xstate_comp();
|
|
print_xstate_offset_size();
|
|
|
|
pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is %d bytes, using '%s' format.\n",
|
|
xfeatures_mask,
|
|
fpu_kernel_xstate_size,
|
|
boot_cpu_has(X86_FEATURE_XSAVES) ? "compacted" : "standard");
|
|
return;
|
|
|
|
out_disable:
|
|
/* something went wrong, try to boot without any XSAVE support */
|
|
fpu__init_disable_system_xstate();
|
|
}
|
|
|
|
/*
|
|
* Restore minimal FPU state after suspend:
|
|
*/
|
|
void fpu__resume_cpu(void)
|
|
{
|
|
/*
|
|
* Restore XCR0 on xsave capable CPUs:
|
|
*/
|
|
if (boot_cpu_has(X86_FEATURE_XSAVE))
|
|
xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask);
|
|
}
|
|
|
|
/*
|
|
* Given an xstate feature mask, calculate where in the xsave
|
|
* buffer the state is. Callers should ensure that the buffer
|
|
* is valid.
|
|
*
|
|
* Note: does not work for compacted buffers.
|
|
*/
|
|
void *__raw_xsave_addr(struct xregs_state *xsave, int xstate_feature_mask)
|
|
{
|
|
int feature_nr = fls64(xstate_feature_mask) - 1;
|
|
|
|
if (!xfeature_enabled(feature_nr)) {
|
|
WARN_ON_FPU(1);
|
|
return NULL;
|
|
}
|
|
|
|
return (void *)xsave + xstate_comp_offsets[feature_nr];
|
|
}
|
|
/*
|
|
* Given the xsave area and a state inside, this function returns the
|
|
* address of the state.
|
|
*
|
|
* This is the API that is called to get xstate address in either
|
|
* standard format or compacted format of xsave area.
|
|
*
|
|
* Note that if there is no data for the field in the xsave buffer
|
|
* this will return NULL.
|
|
*
|
|
* Inputs:
|
|
* xstate: the thread's storage area for all FPU data
|
|
* xstate_feature: state which is defined in xsave.h (e.g.
|
|
* XFEATURE_MASK_FP, XFEATURE_MASK_SSE, etc...)
|
|
* Output:
|
|
* address of the state in the xsave area, or NULL if the
|
|
* field is not present in the xsave buffer.
|
|
*/
|
|
void *get_xsave_addr(struct xregs_state *xsave, int xstate_feature)
|
|
{
|
|
/*
|
|
* Do we even *have* xsave state?
|
|
*/
|
|
if (!boot_cpu_has(X86_FEATURE_XSAVE))
|
|
return NULL;
|
|
|
|
/*
|
|
* We should not ever be requesting features that we
|
|
* have not enabled. Remember that pcntxt_mask is
|
|
* what we write to the XCR0 register.
|
|
*/
|
|
WARN_ONCE(!(xfeatures_mask & xstate_feature),
|
|
"get of unsupported state");
|
|
/*
|
|
* This assumes the last 'xsave*' instruction to
|
|
* have requested that 'xstate_feature' be saved.
|
|
* If it did not, we might be seeing and old value
|
|
* of the field in the buffer.
|
|
*
|
|
* This can happen because the last 'xsave' did not
|
|
* request that this feature be saved (unlikely)
|
|
* or because the "init optimization" caused it
|
|
* to not be saved.
|
|
*/
|
|
if (!(xsave->header.xfeatures & xstate_feature))
|
|
return NULL;
|
|
|
|
return __raw_xsave_addr(xsave, xstate_feature);
|
|
}
|
|
EXPORT_SYMBOL_GPL(get_xsave_addr);
|
|
|
|
/*
|
|
* This wraps up the common operations that need to occur when retrieving
|
|
* data from xsave state. It first ensures that the current task was
|
|
* using the FPU and retrieves the data in to a buffer. It then calculates
|
|
* the offset of the requested field in the buffer.
|
|
*
|
|
* This function is safe to call whether the FPU is in use or not.
|
|
*
|
|
* Note that this only works on the current task.
|
|
*
|
|
* Inputs:
|
|
* @xsave_state: state which is defined in xsave.h (e.g. XFEATURE_MASK_FP,
|
|
* XFEATURE_MASK_SSE, etc...)
|
|
* Output:
|
|
* address of the state in the xsave area or NULL if the state
|
|
* is not present or is in its 'init state'.
|
|
*/
|
|
const void *get_xsave_field_ptr(int xsave_state)
|
|
{
|
|
struct fpu *fpu = ¤t->thread.fpu;
|
|
|
|
if (!fpu->fpstate_active)
|
|
return NULL;
|
|
/*
|
|
* fpu__save() takes the CPU's xstate registers
|
|
* and saves them off to the 'fpu memory buffer.
|
|
*/
|
|
fpu__save(fpu);
|
|
|
|
return get_xsave_addr(&fpu->state.xsave, xsave_state);
|
|
}
|
|
|
|
#ifdef CONFIG_ARCH_HAS_PKEYS
|
|
|
|
#define NR_VALID_PKRU_BITS (CONFIG_NR_PROTECTION_KEYS * 2)
|
|
#define PKRU_VALID_MASK (NR_VALID_PKRU_BITS - 1)
|
|
/*
|
|
* This will go out and modify PKRU register to set the access
|
|
* rights for @pkey to @init_val.
|
|
*/
|
|
int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
|
|
unsigned long init_val)
|
|
{
|
|
u32 old_pkru;
|
|
int pkey_shift = (pkey * PKRU_BITS_PER_PKEY);
|
|
u32 new_pkru_bits = 0;
|
|
|
|
/*
|
|
* This check implies XSAVE support. OSPKE only gets
|
|
* set if we enable XSAVE and we enable PKU in XCR0.
|
|
*/
|
|
if (!boot_cpu_has(X86_FEATURE_OSPKE))
|
|
return -EINVAL;
|
|
|
|
/* Set the bits we need in PKRU: */
|
|
if (init_val & PKEY_DISABLE_ACCESS)
|
|
new_pkru_bits |= PKRU_AD_BIT;
|
|
if (init_val & PKEY_DISABLE_WRITE)
|
|
new_pkru_bits |= PKRU_WD_BIT;
|
|
|
|
/* Shift the bits in to the correct place in PKRU for pkey: */
|
|
new_pkru_bits <<= pkey_shift;
|
|
|
|
/* Get old PKRU and mask off any old bits in place: */
|
|
old_pkru = read_pkru();
|
|
old_pkru &= ~((PKRU_AD_BIT|PKRU_WD_BIT) << pkey_shift);
|
|
|
|
/* Write old part along with new part: */
|
|
write_pkru(old_pkru | new_pkru_bits);
|
|
|
|
return 0;
|
|
}
|
|
#endif /* ! CONFIG_ARCH_HAS_PKEYS */
|
|
|
|
/*
|
|
* This is similar to user_regset_copyout(), but will not add offset to
|
|
* the source data pointer or increment pos, count, kbuf, and ubuf.
|
|
*/
|
|
static inline int xstate_copyout(unsigned int pos, unsigned int count,
|
|
void *kbuf, void __user *ubuf,
|
|
const void *data, const int start_pos,
|
|
const int end_pos)
|
|
{
|
|
if ((count == 0) || (pos < start_pos))
|
|
return 0;
|
|
|
|
if (end_pos < 0 || pos < end_pos) {
|
|
unsigned int copy = (end_pos < 0 ? count : min(count, end_pos - pos));
|
|
|
|
if (kbuf) {
|
|
memcpy(kbuf + pos, data, copy);
|
|
} else {
|
|
if (__copy_to_user(ubuf + pos, data, copy))
|
|
return -EFAULT;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Convert from kernel XSAVES compacted format to standard format and copy
|
|
* to a ptrace buffer. It supports partial copy but pos always starts from
|
|
* zero. This is called from xstateregs_get() and there we check the CPU
|
|
* has XSAVES.
|
|
*/
|
|
int copyout_from_xsaves(unsigned int pos, unsigned int count, void *kbuf,
|
|
void __user *ubuf, struct xregs_state *xsave)
|
|
{
|
|
unsigned int offset, size;
|
|
int ret, i;
|
|
struct xstate_header header;
|
|
|
|
/*
|
|
* Currently copy_regset_to_user() starts from pos 0:
|
|
*/
|
|
if (unlikely(pos != 0))
|
|
return -EFAULT;
|
|
|
|
/*
|
|
* The destination is a ptrace buffer; we put in only user xstates:
|
|
*/
|
|
memset(&header, 0, sizeof(header));
|
|
header.xfeatures = xsave->header.xfeatures;
|
|
header.xfeatures &= ~XFEATURE_MASK_SUPERVISOR;
|
|
|
|
/*
|
|
* Copy xregs_state->header:
|
|
*/
|
|
offset = offsetof(struct xregs_state, header);
|
|
size = sizeof(header);
|
|
|
|
ret = xstate_copyout(offset, size, kbuf, ubuf, &header, 0, count);
|
|
|
|
if (ret)
|
|
return ret;
|
|
|
|
for (i = 0; i < XFEATURE_MAX; i++) {
|
|
/*
|
|
* Copy only in-use xstates:
|
|
*/
|
|
if ((header.xfeatures >> i) & 1) {
|
|
void *src = __raw_xsave_addr(xsave, 1 << i);
|
|
|
|
offset = xstate_offsets[i];
|
|
size = xstate_sizes[i];
|
|
|
|
ret = xstate_copyout(offset, size, kbuf, ubuf, src, 0, count);
|
|
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (offset + size >= count)
|
|
break;
|
|
}
|
|
|
|
}
|
|
|
|
/*
|
|
* Fill xsave->i387.sw_reserved value for ptrace frame:
|
|
*/
|
|
offset = offsetof(struct fxregs_state, sw_reserved);
|
|
size = sizeof(xstate_fx_sw_bytes);
|
|
|
|
ret = xstate_copyout(offset, size, kbuf, ubuf, xstate_fx_sw_bytes, 0, count);
|
|
|
|
if (ret)
|
|
return ret;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Convert from a ptrace standard-format buffer to kernel XSAVES format
|
|
* and copy to the target thread. This is called from xstateregs_set() and
|
|
* there we check the CPU has XSAVES and a whole standard-sized buffer
|
|
* exists.
|
|
*/
|
|
int copyin_to_xsaves(const void *kbuf, const void __user *ubuf,
|
|
struct xregs_state *xsave)
|
|
{
|
|
unsigned int offset, size;
|
|
int i;
|
|
u64 xfeatures;
|
|
u64 allowed_features;
|
|
|
|
offset = offsetof(struct xregs_state, header);
|
|
size = sizeof(xfeatures);
|
|
|
|
if (kbuf) {
|
|
memcpy(&xfeatures, kbuf + offset, size);
|
|
} else {
|
|
if (__copy_from_user(&xfeatures, ubuf + offset, size))
|
|
return -EFAULT;
|
|
}
|
|
|
|
/*
|
|
* Reject if the user sets any disabled or supervisor features:
|
|
*/
|
|
allowed_features = xfeatures_mask & ~XFEATURE_MASK_SUPERVISOR;
|
|
|
|
if (xfeatures & ~allowed_features)
|
|
return -EINVAL;
|
|
|
|
for (i = 0; i < XFEATURE_MAX; i++) {
|
|
u64 mask = ((u64)1 << i);
|
|
|
|
if (xfeatures & mask) {
|
|
void *dst = __raw_xsave_addr(xsave, 1 << i);
|
|
|
|
offset = xstate_offsets[i];
|
|
size = xstate_sizes[i];
|
|
|
|
if (kbuf) {
|
|
memcpy(dst, kbuf + offset, size);
|
|
} else {
|
|
if (__copy_from_user(dst, ubuf + offset, size))
|
|
return -EFAULT;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* The state that came in from userspace was user-state only.
|
|
* Mask all the user states out of 'xfeatures':
|
|
*/
|
|
xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR;
|
|
|
|
/*
|
|
* Add back in the features that came in from userspace:
|
|
*/
|
|
xsave->header.xfeatures |= xfeatures;
|
|
|
|
return 0;
|
|
}
|