mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-15 15:36:56 +07:00
a474e67c91
What, you didn't realize that SYSENTER and SYSCALL were actually the same thing? :) Unlike the old code, this actually passes the ptrace_syscall_32 test on AMD systems. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/b74615af58d785aa02d917213ec64e2022a2c796.1444091585.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
282 lines
8.4 KiB
ArmAsm
282 lines
8.4 KiB
ArmAsm
/*
|
|
* Compatibility mode system call entry point for x86-64.
|
|
*
|
|
* Copyright 2000-2002 Andi Kleen, SuSE Labs.
|
|
*/
|
|
#include "calling.h"
|
|
#include <asm/asm-offsets.h>
|
|
#include <asm/current.h>
|
|
#include <asm/errno.h>
|
|
#include <asm/ia32_unistd.h>
|
|
#include <asm/thread_info.h>
|
|
#include <asm/segment.h>
|
|
#include <asm/irqflags.h>
|
|
#include <asm/asm.h>
|
|
#include <asm/smap.h>
|
|
#include <linux/linkage.h>
|
|
#include <linux/err.h>
|
|
|
|
.section .entry.text, "ax"
|
|
|
|
#ifdef CONFIG_PARAVIRT
|
|
ENTRY(native_usergs_sysret32)
|
|
swapgs
|
|
sysretl
|
|
ENDPROC(native_usergs_sysret32)
|
|
#endif
|
|
|
|
/*
|
|
* 32-bit SYSENTER instruction entry.
|
|
*
|
|
* SYSENTER loads ss, rsp, cs, and rip from previously programmed MSRs.
|
|
* IF and VM in rflags are cleared (IOW: interrupts are off).
|
|
* SYSENTER does not save anything on the stack,
|
|
* and does not save old rip (!!!) and rflags.
|
|
*
|
|
* Arguments:
|
|
* eax system call number
|
|
* ebx arg1
|
|
* ecx arg2
|
|
* edx arg3
|
|
* esi arg4
|
|
* edi arg5
|
|
* ebp user stack
|
|
* 0(%ebp) arg6
|
|
*
|
|
* This is purely a fast path. For anything complicated we use the int 0x80
|
|
* path below. We set up a complete hardware stack frame to share code
|
|
* with the int 0x80 path.
|
|
*/
|
|
ENTRY(entry_SYSENTER_compat)
|
|
/* Interrupts are off on entry. */
|
|
SWAPGS_UNSAFE_STACK
|
|
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
|
|
|
|
/*
|
|
* User tracing code (ptrace or signal handlers) might assume that
|
|
* the saved RAX contains a 32-bit number when we're invoking a 32-bit
|
|
* syscall. Just in case the high bits are nonzero, zero-extend
|
|
* the syscall number. (This could almost certainly be deleted
|
|
* with no ill effects.)
|
|
*/
|
|
movl %eax, %eax
|
|
|
|
/* Construct struct pt_regs on stack */
|
|
pushq $__USER32_DS /* pt_regs->ss */
|
|
pushq %rcx /* pt_regs->sp */
|
|
|
|
/*
|
|
* Push flags. This is nasty. First, interrupts are currently
|
|
* off, but we need pt_regs->flags to have IF set. Second, even
|
|
* if TF was set when SYSENTER started, it's clear by now. We fix
|
|
* that later using TIF_SINGLESTEP.
|
|
*/
|
|
pushfq /* pt_regs->flags (except IF = 0) */
|
|
orl $X86_EFLAGS_IF, (%rsp) /* Fix saved flags */
|
|
ASM_CLAC /* Clear AC after saving FLAGS */
|
|
|
|
pushq $__USER32_CS /* pt_regs->cs */
|
|
xorq %r8,%r8
|
|
pushq %r8 /* pt_regs->ip = 0 (placeholder) */
|
|
pushq %rax /* pt_regs->orig_ax */
|
|
pushq %rdi /* pt_regs->di */
|
|
pushq %rsi /* pt_regs->si */
|
|
pushq %rdx /* pt_regs->dx */
|
|
pushq %rcx /* pt_regs->cx (will be overwritten) */
|
|
pushq $-ENOSYS /* pt_regs->ax */
|
|
pushq %r8 /* pt_regs->r8 = 0 */
|
|
pushq %r8 /* pt_regs->r9 = 0 */
|
|
pushq %r8 /* pt_regs->r10 = 0 */
|
|
pushq %r8 /* pt_regs->r11 = 0 */
|
|
pushq %rbx /* pt_regs->rbx */
|
|
pushq %rbp /* pt_regs->rbp */
|
|
pushq %r8 /* pt_regs->r12 = 0 */
|
|
pushq %r8 /* pt_regs->r13 = 0 */
|
|
pushq %r8 /* pt_regs->r14 = 0 */
|
|
pushq %r8 /* pt_regs->r15 = 0 */
|
|
cld
|
|
|
|
/*
|
|
* Sysenter doesn't filter flags, so we need to clear NT
|
|
* ourselves. To save a few cycles, we can check whether
|
|
* NT was set instead of doing an unconditional popfq.
|
|
* This needs to happen before enabling interrupts so that
|
|
* we don't get preempted with NT set.
|
|
*/
|
|
testl $X86_EFLAGS_NT, EFLAGS(%rsp)
|
|
jnz sysenter_fix_flags
|
|
sysenter_flags_fixed:
|
|
|
|
/*
|
|
* User mode is traced as though IRQs are on, and SYSENTER
|
|
* turned them off.
|
|
*/
|
|
TRACE_IRQS_OFF
|
|
|
|
movq %rsp, %rdi
|
|
call do_fast_syscall_32
|
|
jmp .Lsyscall_32_done
|
|
|
|
sysenter_fix_flags:
|
|
pushq $X86_EFLAGS_FIXED
|
|
popfq
|
|
jmp sysenter_flags_fixed
|
|
ENDPROC(entry_SYSENTER_compat)
|
|
|
|
/*
|
|
* 32-bit SYSCALL instruction entry.
|
|
*
|
|
* 32-bit SYSCALL saves rip to rcx, clears rflags.RF, then saves rflags to r11,
|
|
* then loads new ss, cs, and rip from previously programmed MSRs.
|
|
* rflags gets masked by a value from another MSR (so CLD and CLAC
|
|
* are not needed). SYSCALL does not save anything on the stack
|
|
* and does not change rsp.
|
|
*
|
|
* Note: rflags saving+masking-with-MSR happens only in Long mode
|
|
* (in legacy 32-bit mode, IF, RF and VM bits are cleared and that's it).
|
|
* Don't get confused: rflags saving+masking depends on Long Mode Active bit
|
|
* (EFER.LMA=1), NOT on bitness of userspace where SYSCALL executes
|
|
* or target CS descriptor's L bit (SYSCALL does not read segment descriptors).
|
|
*
|
|
* Arguments:
|
|
* eax system call number
|
|
* ecx return address
|
|
* ebx arg1
|
|
* ebp arg2 (note: not saved in the stack frame, should not be touched)
|
|
* edx arg3
|
|
* esi arg4
|
|
* edi arg5
|
|
* esp user stack
|
|
* 0(%esp) arg6
|
|
*/
|
|
ENTRY(entry_SYSCALL_compat)
|
|
/* Interrupts are off on entry. */
|
|
SWAPGS_UNSAFE_STACK
|
|
|
|
/* Stash user ESP and switch to the kernel stack. */
|
|
movl %esp, %r8d
|
|
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
|
|
|
|
/* Zero-extending 32-bit regs, do not remove */
|
|
movl %eax, %eax
|
|
|
|
/* Construct struct pt_regs on stack */
|
|
pushq $__USER32_DS /* pt_regs->ss */
|
|
pushq %r8 /* pt_regs->sp */
|
|
pushq %r11 /* pt_regs->flags */
|
|
pushq $__USER32_CS /* pt_regs->cs */
|
|
pushq %rcx /* pt_regs->ip */
|
|
pushq %rax /* pt_regs->orig_ax */
|
|
pushq %rdi /* pt_regs->di */
|
|
pushq %rsi /* pt_regs->si */
|
|
pushq %rdx /* pt_regs->dx */
|
|
pushq %rcx /* pt_regs->cx (will be overwritten) */
|
|
pushq $-ENOSYS /* pt_regs->ax */
|
|
xorq %r8,%r8
|
|
pushq %r8 /* pt_regs->r8 = 0 */
|
|
pushq %r8 /* pt_regs->r9 = 0 */
|
|
pushq %r8 /* pt_regs->r10 = 0 */
|
|
pushq %r8 /* pt_regs->r11 = 0 */
|
|
pushq %rbx /* pt_regs->rbx */
|
|
pushq %rbp /* pt_regs->rbp */
|
|
pushq %r8 /* pt_regs->r12 = 0 */
|
|
pushq %r8 /* pt_regs->r13 = 0 */
|
|
pushq %r8 /* pt_regs->r14 = 0 */
|
|
pushq %r8 /* pt_regs->r15 = 0 */
|
|
|
|
/*
|
|
* User mode is traced as though IRQs are on, and SYSENTER
|
|
* turned them off.
|
|
*/
|
|
TRACE_IRQS_OFF
|
|
|
|
movq %rsp, %rdi
|
|
call do_fast_syscall_32
|
|
jmp .Lsyscall_32_done
|
|
END(entry_SYSCALL_compat)
|
|
|
|
/*
|
|
* Emulated IA32 system calls via int 0x80.
|
|
*
|
|
* Arguments:
|
|
* eax system call number
|
|
* ebx arg1
|
|
* ecx arg2
|
|
* edx arg3
|
|
* esi arg4
|
|
* edi arg5
|
|
* ebp arg6 (note: not saved in the stack frame, should not be touched)
|
|
*
|
|
* Notes:
|
|
* Uses the same stack frame as the x86-64 version.
|
|
* All registers except eax must be saved (but ptrace may violate that).
|
|
* Arguments are zero extended. For system calls that want sign extension and
|
|
* take long arguments a wrapper is needed. Most calls can just be called
|
|
* directly.
|
|
* Assumes it is only called from user space and entered with interrupts off.
|
|
*/
|
|
|
|
ENTRY(entry_INT80_compat)
|
|
/*
|
|
* Interrupts are off on entry.
|
|
*/
|
|
PARAVIRT_ADJUST_EXCEPTION_FRAME
|
|
SWAPGS
|
|
|
|
/*
|
|
* User tracing code (ptrace or signal handlers) might assume that
|
|
* the saved RAX contains a 32-bit number when we're invoking a 32-bit
|
|
* syscall. Just in case the high bits are nonzero, zero-extend
|
|
* the syscall number. (This could almost certainly be deleted
|
|
* with no ill effects.)
|
|
*/
|
|
movl %eax, %eax
|
|
|
|
/* Construct struct pt_regs on stack (iret frame is already on stack) */
|
|
pushq %rax /* pt_regs->orig_ax */
|
|
pushq %rdi /* pt_regs->di */
|
|
pushq %rsi /* pt_regs->si */
|
|
pushq %rdx /* pt_regs->dx */
|
|
pushq %rcx /* pt_regs->cx */
|
|
pushq $-ENOSYS /* pt_regs->ax */
|
|
xorq %r8,%r8
|
|
pushq %r8 /* pt_regs->r8 = 0 */
|
|
pushq %r8 /* pt_regs->r9 = 0 */
|
|
pushq %r8 /* pt_regs->r10 = 0 */
|
|
pushq %r8 /* pt_regs->r11 = 0 */
|
|
pushq %rbx /* pt_regs->rbx */
|
|
pushq %rbp /* pt_regs->rbp */
|
|
pushq %r12 /* pt_regs->r12 */
|
|
pushq %r13 /* pt_regs->r13 */
|
|
pushq %r14 /* pt_regs->r14 */
|
|
pushq %r15 /* pt_regs->r15 */
|
|
cld
|
|
|
|
/*
|
|
* User mode is traced as though IRQs are on, and the interrupt
|
|
* gate turned them off.
|
|
*/
|
|
TRACE_IRQS_OFF
|
|
|
|
movq %rsp, %rdi
|
|
call do_int80_syscall_32
|
|
.Lsyscall_32_done:
|
|
|
|
/* Go back to user mode. */
|
|
TRACE_IRQS_ON
|
|
SWAPGS
|
|
jmp restore_regs_and_iret
|
|
END(entry_INT80_compat)
|
|
|
|
ALIGN
|
|
GLOBAL(stub32_clone)
|
|
/*
|
|
* The 32-bit clone ABI is: clone(..., int tls_val, int *child_tidptr).
|
|
* The 64-bit clone ABI is: clone(..., int *child_tidptr, int tls_val).
|
|
*
|
|
* The native 64-bit kernel's sys_clone() implements the latter,
|
|
* so we need to swap arguments here before calling it:
|
|
*/
|
|
xchg %r8, %rcx
|
|
jmp sys_clone
|