mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-14 03:56:43 +07:00
71f6e58e5e
Along similar lines as commit 9326638cbe ("kprobes, x86: Use NOKPROBE_SYMBOL()
instead of __kprobes annotation"), convert __kprobes annotation to either
NOKPROBE_SYMBOL() or nokprobe_inline. The latter forces inlining, in which case
the caller needs to be added to NOKPROBE_SYMBOL().
Also:
- blacklist arch_deref_entry_point(), and
- convert a few regular inlines to nokprobe_inline in lib/sstep.c
A key benefit is the ability to detect such symbols as being
blacklisted. Before this patch:
$ cat /sys/kernel/debug/kprobes/blacklist | grep read_mem
$ perf probe read_mem
Failed to write event: Invalid argument
Error: Failed to add events.
$ dmesg | tail -1
[ 3736.112815] Could not insert probe at _text+10014968: -22
After patch:
$ cat /sys/kernel/debug/kprobes/blacklist | grep read_mem
0xc000000000072b50-0xc000000000072d20 read_mem
$ perf probe read_mem
read_mem is blacklisted function, skip it.
Added new events:
(null):(null) (on read_mem)
probe:read_mem (on read_mem)
You can now use it in all perf tools, such as:
perf record -e probe:read_mem -aR sleep 1
$ grep " read_mem" /proc/kallsyms
c000000000072b50 t read_mem
c0000000005f3b40 t read_mem
$ cat /sys/kernel/debug/kprobes/list
c0000000005f3b48 k read_mem+0x8 [DISABLED]
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
[mpe: Minor change log formatting, fix up some conflicts]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
517 lines
14 KiB
C
517 lines
14 KiB
C
/*
|
|
* Copyright 2008 Michael Ellerman, IBM Corporation.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/kprobes.h>
|
|
#include <linux/vmalloc.h>
|
|
#include <linux/init.h>
|
|
#include <linux/mm.h>
|
|
#include <asm/page.h>
|
|
#include <asm/code-patching.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/kprobes.h>
|
|
|
|
|
|
int patch_instruction(unsigned int *addr, unsigned int instr)
|
|
{
|
|
int err;
|
|
|
|
__put_user_size(instr, addr, 4, err);
|
|
if (err)
|
|
return err;
|
|
asm ("dcbst 0, %0; sync; icbi 0,%0; sync; isync" : : "r" (addr));
|
|
return 0;
|
|
}
|
|
|
|
int patch_branch(unsigned int *addr, unsigned long target, int flags)
|
|
{
|
|
return patch_instruction(addr, create_branch(addr, target, flags));
|
|
}
|
|
|
|
bool is_offset_in_branch_range(long offset)
|
|
{
|
|
/*
|
|
* Powerpc branch instruction is :
|
|
*
|
|
* 0 6 30 31
|
|
* +---------+----------------+---+---+
|
|
* | opcode | LI |AA |LK |
|
|
* +---------+----------------+---+---+
|
|
* Where AA = 0 and LK = 0
|
|
*
|
|
* LI is a signed 24 bits integer. The real branch offset is computed
|
|
* by: imm32 = SignExtend(LI:'0b00', 32);
|
|
*
|
|
* So the maximum forward branch should be:
|
|
* (0x007fffff << 2) = 0x01fffffc = 0x1fffffc
|
|
* The maximum backward branch should be:
|
|
* (0xff800000 << 2) = 0xfe000000 = -0x2000000
|
|
*/
|
|
return (offset >= -0x2000000 && offset <= 0x1fffffc && !(offset & 0x3));
|
|
}
|
|
|
|
/*
|
|
* Helper to check if a given instruction is a conditional branch
|
|
* Derived from the conditional checks in analyse_instr()
|
|
*/
|
|
bool is_conditional_branch(unsigned int instr)
|
|
{
|
|
unsigned int opcode = instr >> 26;
|
|
|
|
if (opcode == 16) /* bc, bca, bcl, bcla */
|
|
return true;
|
|
if (opcode == 19) {
|
|
switch ((instr >> 1) & 0x3ff) {
|
|
case 16: /* bclr, bclrl */
|
|
case 528: /* bcctr, bcctrl */
|
|
case 560: /* bctar, bctarl */
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
NOKPROBE_SYMBOL(is_conditional_branch);
|
|
|
|
unsigned int create_branch(const unsigned int *addr,
|
|
unsigned long target, int flags)
|
|
{
|
|
unsigned int instruction;
|
|
long offset;
|
|
|
|
offset = target;
|
|
if (! (flags & BRANCH_ABSOLUTE))
|
|
offset = offset - (unsigned long)addr;
|
|
|
|
/* Check we can represent the target in the instruction format */
|
|
if (!is_offset_in_branch_range(offset))
|
|
return 0;
|
|
|
|
/* Mask out the flags and target, so they don't step on each other. */
|
|
instruction = 0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC);
|
|
|
|
return instruction;
|
|
}
|
|
|
|
unsigned int create_cond_branch(const unsigned int *addr,
|
|
unsigned long target, int flags)
|
|
{
|
|
unsigned int instruction;
|
|
long offset;
|
|
|
|
offset = target;
|
|
if (! (flags & BRANCH_ABSOLUTE))
|
|
offset = offset - (unsigned long)addr;
|
|
|
|
/* Check we can represent the target in the instruction format */
|
|
if (offset < -0x8000 || offset > 0x7FFF || offset & 0x3)
|
|
return 0;
|
|
|
|
/* Mask out the flags and target, so they don't step on each other. */
|
|
instruction = 0x40000000 | (flags & 0x3FF0003) | (offset & 0xFFFC);
|
|
|
|
return instruction;
|
|
}
|
|
|
|
static unsigned int branch_opcode(unsigned int instr)
|
|
{
|
|
return (instr >> 26) & 0x3F;
|
|
}
|
|
|
|
static int instr_is_branch_iform(unsigned int instr)
|
|
{
|
|
return branch_opcode(instr) == 18;
|
|
}
|
|
|
|
static int instr_is_branch_bform(unsigned int instr)
|
|
{
|
|
return branch_opcode(instr) == 16;
|
|
}
|
|
|
|
int instr_is_relative_branch(unsigned int instr)
|
|
{
|
|
if (instr & BRANCH_ABSOLUTE)
|
|
return 0;
|
|
|
|
return instr_is_branch_iform(instr) || instr_is_branch_bform(instr);
|
|
}
|
|
|
|
static unsigned long branch_iform_target(const unsigned int *instr)
|
|
{
|
|
signed long imm;
|
|
|
|
imm = *instr & 0x3FFFFFC;
|
|
|
|
/* If the top bit of the immediate value is set this is negative */
|
|
if (imm & 0x2000000)
|
|
imm -= 0x4000000;
|
|
|
|
if ((*instr & BRANCH_ABSOLUTE) == 0)
|
|
imm += (unsigned long)instr;
|
|
|
|
return (unsigned long)imm;
|
|
}
|
|
|
|
static unsigned long branch_bform_target(const unsigned int *instr)
|
|
{
|
|
signed long imm;
|
|
|
|
imm = *instr & 0xFFFC;
|
|
|
|
/* If the top bit of the immediate value is set this is negative */
|
|
if (imm & 0x8000)
|
|
imm -= 0x10000;
|
|
|
|
if ((*instr & BRANCH_ABSOLUTE) == 0)
|
|
imm += (unsigned long)instr;
|
|
|
|
return (unsigned long)imm;
|
|
}
|
|
|
|
unsigned long branch_target(const unsigned int *instr)
|
|
{
|
|
if (instr_is_branch_iform(*instr))
|
|
return branch_iform_target(instr);
|
|
else if (instr_is_branch_bform(*instr))
|
|
return branch_bform_target(instr);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr)
|
|
{
|
|
if (instr_is_branch_iform(*instr) || instr_is_branch_bform(*instr))
|
|
return branch_target(instr) == addr;
|
|
|
|
return 0;
|
|
}
|
|
|
|
unsigned int translate_branch(const unsigned int *dest, const unsigned int *src)
|
|
{
|
|
unsigned long target;
|
|
|
|
target = branch_target(src);
|
|
|
|
if (instr_is_branch_iform(*src))
|
|
return create_branch(dest, target, *src);
|
|
else if (instr_is_branch_bform(*src))
|
|
return create_cond_branch(dest, target, *src);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_PPC_BOOK3E_64
|
|
void __patch_exception(int exc, unsigned long addr)
|
|
{
|
|
extern unsigned int interrupt_base_book3e;
|
|
unsigned int *ibase = &interrupt_base_book3e;
|
|
|
|
/* Our exceptions vectors start with a NOP and -then- a branch
|
|
* to deal with single stepping from userspace which stops on
|
|
* the second instruction. Thus we need to patch the second
|
|
* instruction of the exception, not the first one
|
|
*/
|
|
|
|
patch_branch(ibase + (exc / 4) + 1, addr, 0);
|
|
}
|
|
#endif
|
|
|
|
#ifdef CONFIG_CODE_PATCHING_SELFTEST
|
|
|
|
static void __init test_trampoline(void)
|
|
{
|
|
asm ("nop;\n");
|
|
}
|
|
|
|
#define check(x) \
|
|
if (!(x)) printk("code-patching: test failed at line %d\n", __LINE__);
|
|
|
|
static void __init test_branch_iform(void)
|
|
{
|
|
unsigned int instr;
|
|
unsigned long addr;
|
|
|
|
addr = (unsigned long)&instr;
|
|
|
|
/* The simplest case, branch to self, no flags */
|
|
check(instr_is_branch_iform(0x48000000));
|
|
/* All bits of target set, and flags */
|
|
check(instr_is_branch_iform(0x4bffffff));
|
|
/* High bit of opcode set, which is wrong */
|
|
check(!instr_is_branch_iform(0xcbffffff));
|
|
/* Middle bits of opcode set, which is wrong */
|
|
check(!instr_is_branch_iform(0x7bffffff));
|
|
|
|
/* Simplest case, branch to self with link */
|
|
check(instr_is_branch_iform(0x48000001));
|
|
/* All bits of targets set */
|
|
check(instr_is_branch_iform(0x4bfffffd));
|
|
/* Some bits of targets set */
|
|
check(instr_is_branch_iform(0x4bff00fd));
|
|
/* Must be a valid branch to start with */
|
|
check(!instr_is_branch_iform(0x7bfffffd));
|
|
|
|
/* Absolute branch to 0x100 */
|
|
instr = 0x48000103;
|
|
check(instr_is_branch_to_addr(&instr, 0x100));
|
|
/* Absolute branch to 0x420fc */
|
|
instr = 0x480420ff;
|
|
check(instr_is_branch_to_addr(&instr, 0x420fc));
|
|
/* Maximum positive relative branch, + 20MB - 4B */
|
|
instr = 0x49fffffc;
|
|
check(instr_is_branch_to_addr(&instr, addr + 0x1FFFFFC));
|
|
/* Smallest negative relative branch, - 4B */
|
|
instr = 0x4bfffffc;
|
|
check(instr_is_branch_to_addr(&instr, addr - 4));
|
|
/* Largest negative relative branch, - 32 MB */
|
|
instr = 0x4a000000;
|
|
check(instr_is_branch_to_addr(&instr, addr - 0x2000000));
|
|
|
|
/* Branch to self, with link */
|
|
instr = create_branch(&instr, addr, BRANCH_SET_LINK);
|
|
check(instr_is_branch_to_addr(&instr, addr));
|
|
|
|
/* Branch to self - 0x100, with link */
|
|
instr = create_branch(&instr, addr - 0x100, BRANCH_SET_LINK);
|
|
check(instr_is_branch_to_addr(&instr, addr - 0x100));
|
|
|
|
/* Branch to self + 0x100, no link */
|
|
instr = create_branch(&instr, addr + 0x100, 0);
|
|
check(instr_is_branch_to_addr(&instr, addr + 0x100));
|
|
|
|
/* Maximum relative negative offset, - 32 MB */
|
|
instr = create_branch(&instr, addr - 0x2000000, BRANCH_SET_LINK);
|
|
check(instr_is_branch_to_addr(&instr, addr - 0x2000000));
|
|
|
|
/* Out of range relative negative offset, - 32 MB + 4*/
|
|
instr = create_branch(&instr, addr - 0x2000004, BRANCH_SET_LINK);
|
|
check(instr == 0);
|
|
|
|
/* Out of range relative positive offset, + 32 MB */
|
|
instr = create_branch(&instr, addr + 0x2000000, BRANCH_SET_LINK);
|
|
check(instr == 0);
|
|
|
|
/* Unaligned target */
|
|
instr = create_branch(&instr, addr + 3, BRANCH_SET_LINK);
|
|
check(instr == 0);
|
|
|
|
/* Check flags are masked correctly */
|
|
instr = create_branch(&instr, addr, 0xFFFFFFFC);
|
|
check(instr_is_branch_to_addr(&instr, addr));
|
|
check(instr == 0x48000000);
|
|
}
|
|
|
|
static void __init test_create_function_call(void)
|
|
{
|
|
unsigned int *iptr;
|
|
unsigned long dest;
|
|
|
|
/* Check we can create a function call */
|
|
iptr = (unsigned int *)ppc_function_entry(test_trampoline);
|
|
dest = ppc_function_entry(test_create_function_call);
|
|
patch_instruction(iptr, create_branch(iptr, dest, BRANCH_SET_LINK));
|
|
check(instr_is_branch_to_addr(iptr, dest));
|
|
}
|
|
|
|
static void __init test_branch_bform(void)
|
|
{
|
|
unsigned long addr;
|
|
unsigned int *iptr, instr, flags;
|
|
|
|
iptr = &instr;
|
|
addr = (unsigned long)iptr;
|
|
|
|
/* The simplest case, branch to self, no flags */
|
|
check(instr_is_branch_bform(0x40000000));
|
|
/* All bits of target set, and flags */
|
|
check(instr_is_branch_bform(0x43ffffff));
|
|
/* High bit of opcode set, which is wrong */
|
|
check(!instr_is_branch_bform(0xc3ffffff));
|
|
/* Middle bits of opcode set, which is wrong */
|
|
check(!instr_is_branch_bform(0x7bffffff));
|
|
|
|
/* Absolute conditional branch to 0x100 */
|
|
instr = 0x43ff0103;
|
|
check(instr_is_branch_to_addr(&instr, 0x100));
|
|
/* Absolute conditional branch to 0x20fc */
|
|
instr = 0x43ff20ff;
|
|
check(instr_is_branch_to_addr(&instr, 0x20fc));
|
|
/* Maximum positive relative conditional branch, + 32 KB - 4B */
|
|
instr = 0x43ff7ffc;
|
|
check(instr_is_branch_to_addr(&instr, addr + 0x7FFC));
|
|
/* Smallest negative relative conditional branch, - 4B */
|
|
instr = 0x43fffffc;
|
|
check(instr_is_branch_to_addr(&instr, addr - 4));
|
|
/* Largest negative relative conditional branch, - 32 KB */
|
|
instr = 0x43ff8000;
|
|
check(instr_is_branch_to_addr(&instr, addr - 0x8000));
|
|
|
|
/* All condition code bits set & link */
|
|
flags = 0x3ff000 | BRANCH_SET_LINK;
|
|
|
|
/* Branch to self */
|
|
instr = create_cond_branch(iptr, addr, flags);
|
|
check(instr_is_branch_to_addr(&instr, addr));
|
|
|
|
/* Branch to self - 0x100 */
|
|
instr = create_cond_branch(iptr, addr - 0x100, flags);
|
|
check(instr_is_branch_to_addr(&instr, addr - 0x100));
|
|
|
|
/* Branch to self + 0x100 */
|
|
instr = create_cond_branch(iptr, addr + 0x100, flags);
|
|
check(instr_is_branch_to_addr(&instr, addr + 0x100));
|
|
|
|
/* Maximum relative negative offset, - 32 KB */
|
|
instr = create_cond_branch(iptr, addr - 0x8000, flags);
|
|
check(instr_is_branch_to_addr(&instr, addr - 0x8000));
|
|
|
|
/* Out of range relative negative offset, - 32 KB + 4*/
|
|
instr = create_cond_branch(iptr, addr - 0x8004, flags);
|
|
check(instr == 0);
|
|
|
|
/* Out of range relative positive offset, + 32 KB */
|
|
instr = create_cond_branch(iptr, addr + 0x8000, flags);
|
|
check(instr == 0);
|
|
|
|
/* Unaligned target */
|
|
instr = create_cond_branch(iptr, addr + 3, flags);
|
|
check(instr == 0);
|
|
|
|
/* Check flags are masked correctly */
|
|
instr = create_cond_branch(iptr, addr, 0xFFFFFFFC);
|
|
check(instr_is_branch_to_addr(&instr, addr));
|
|
check(instr == 0x43FF0000);
|
|
}
|
|
|
|
static void __init test_translate_branch(void)
|
|
{
|
|
unsigned long addr;
|
|
unsigned int *p, *q;
|
|
void *buf;
|
|
|
|
buf = vmalloc(PAGE_ALIGN(0x2000000 + 1));
|
|
check(buf);
|
|
if (!buf)
|
|
return;
|
|
|
|
/* Simple case, branch to self moved a little */
|
|
p = buf;
|
|
addr = (unsigned long)p;
|
|
patch_branch(p, addr, 0);
|
|
check(instr_is_branch_to_addr(p, addr));
|
|
q = p + 1;
|
|
patch_instruction(q, translate_branch(q, p));
|
|
check(instr_is_branch_to_addr(q, addr));
|
|
|
|
/* Maximum negative case, move b . to addr + 32 MB */
|
|
p = buf;
|
|
addr = (unsigned long)p;
|
|
patch_branch(p, addr, 0);
|
|
q = buf + 0x2000000;
|
|
patch_instruction(q, translate_branch(q, p));
|
|
check(instr_is_branch_to_addr(p, addr));
|
|
check(instr_is_branch_to_addr(q, addr));
|
|
check(*q == 0x4a000000);
|
|
|
|
/* Maximum positive case, move x to x - 32 MB + 4 */
|
|
p = buf + 0x2000000;
|
|
addr = (unsigned long)p;
|
|
patch_branch(p, addr, 0);
|
|
q = buf + 4;
|
|
patch_instruction(q, translate_branch(q, p));
|
|
check(instr_is_branch_to_addr(p, addr));
|
|
check(instr_is_branch_to_addr(q, addr));
|
|
check(*q == 0x49fffffc);
|
|
|
|
/* Jump to x + 16 MB moved to x + 20 MB */
|
|
p = buf;
|
|
addr = 0x1000000 + (unsigned long)buf;
|
|
patch_branch(p, addr, BRANCH_SET_LINK);
|
|
q = buf + 0x1400000;
|
|
patch_instruction(q, translate_branch(q, p));
|
|
check(instr_is_branch_to_addr(p, addr));
|
|
check(instr_is_branch_to_addr(q, addr));
|
|
|
|
/* Jump to x + 16 MB moved to x - 16 MB + 4 */
|
|
p = buf + 0x1000000;
|
|
addr = 0x2000000 + (unsigned long)buf;
|
|
patch_branch(p, addr, 0);
|
|
q = buf + 4;
|
|
patch_instruction(q, translate_branch(q, p));
|
|
check(instr_is_branch_to_addr(p, addr));
|
|
check(instr_is_branch_to_addr(q, addr));
|
|
|
|
|
|
/* Conditional branch tests */
|
|
|
|
/* Simple case, branch to self moved a little */
|
|
p = buf;
|
|
addr = (unsigned long)p;
|
|
patch_instruction(p, create_cond_branch(p, addr, 0));
|
|
check(instr_is_branch_to_addr(p, addr));
|
|
q = p + 1;
|
|
patch_instruction(q, translate_branch(q, p));
|
|
check(instr_is_branch_to_addr(q, addr));
|
|
|
|
/* Maximum negative case, move b . to addr + 32 KB */
|
|
p = buf;
|
|
addr = (unsigned long)p;
|
|
patch_instruction(p, create_cond_branch(p, addr, 0xFFFFFFFC));
|
|
q = buf + 0x8000;
|
|
patch_instruction(q, translate_branch(q, p));
|
|
check(instr_is_branch_to_addr(p, addr));
|
|
check(instr_is_branch_to_addr(q, addr));
|
|
check(*q == 0x43ff8000);
|
|
|
|
/* Maximum positive case, move x to x - 32 KB + 4 */
|
|
p = buf + 0x8000;
|
|
addr = (unsigned long)p;
|
|
patch_instruction(p, create_cond_branch(p, addr, 0xFFFFFFFC));
|
|
q = buf + 4;
|
|
patch_instruction(q, translate_branch(q, p));
|
|
check(instr_is_branch_to_addr(p, addr));
|
|
check(instr_is_branch_to_addr(q, addr));
|
|
check(*q == 0x43ff7ffc);
|
|
|
|
/* Jump to x + 12 KB moved to x + 20 KB */
|
|
p = buf;
|
|
addr = 0x3000 + (unsigned long)buf;
|
|
patch_instruction(p, create_cond_branch(p, addr, BRANCH_SET_LINK));
|
|
q = buf + 0x5000;
|
|
patch_instruction(q, translate_branch(q, p));
|
|
check(instr_is_branch_to_addr(p, addr));
|
|
check(instr_is_branch_to_addr(q, addr));
|
|
|
|
/* Jump to x + 8 KB moved to x - 8 KB + 4 */
|
|
p = buf + 0x2000;
|
|
addr = 0x4000 + (unsigned long)buf;
|
|
patch_instruction(p, create_cond_branch(p, addr, 0));
|
|
q = buf + 4;
|
|
patch_instruction(q, translate_branch(q, p));
|
|
check(instr_is_branch_to_addr(p, addr));
|
|
check(instr_is_branch_to_addr(q, addr));
|
|
|
|
/* Free the buffer we were using */
|
|
vfree(buf);
|
|
}
|
|
|
|
static int __init test_code_patching(void)
|
|
{
|
|
printk(KERN_DEBUG "Running code patching self-tests ...\n");
|
|
|
|
test_branch_iform();
|
|
test_branch_bform();
|
|
test_create_function_call();
|
|
test_translate_branch();
|
|
|
|
return 0;
|
|
}
|
|
late_initcall(test_code_patching);
|
|
|
|
#endif /* CONFIG_CODE_PATCHING_SELFTEST */
|