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x86/ibt,paravirt: Use text_gen_insn() for paravirt_patch()

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Upstream commit: ba27d1a808

Less duplication is more better.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154317.697253958@infradead.org
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Zijlstra 2022-03-08 16:30:20 +01:00 committed by Greg Kroah-Hartman
parent b810c58d8b
commit b9d69bfff6
2 changed files with 17 additions and 26 deletions
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20
arch/x86/include/asm/text-patching.h
View File

@ -96,32 +96,40 @@ union text_poke_insn {
};
static __always_inline
void *text_gen_insn(u8 opcode, const void *addr, const void *dest)
void __text_gen_insn(void *buf, u8 opcode, const void *addr, const void *dest, int size)
{
static union text_poke_insn insn; /* per instance */
int size = text_opcode_size(opcode);
union text_poke_insn *insn = buf;
BUG_ON(size < text_opcode_size(opcode));
/*
* Hide the addresses to avoid the compiler folding in constants when
* referencing code, these can mess up annotations like
* ANNOTATE_NOENDBR.
*/
OPTIMIZER_HIDE_VAR(insn);
OPTIMIZER_HIDE_VAR(addr);
OPTIMIZER_HIDE_VAR(dest);
insn.opcode = opcode;
insn->opcode = opcode;
if (size > 1) {
insn.disp = (long)dest - (long)(addr + size);
insn->disp = (long)dest - (long)(addr + size);
if (size == 2) {
/*
* Ensure that for JMP8 the displacement
* actually fits the signed byte.
*/
BUG_ON((insn.disp >> 31) != (insn.disp >> 7));
BUG_ON((insn->disp >> 31) != (insn->disp >> 7));
}
}
}
static __always_inline
void *text_gen_insn(u8 opcode, const void *addr, const void *dest)
{
static union text_poke_insn insn; /* per instance */
__text_gen_insn(&insn, opcode, addr, dest, text_opcode_size(opcode));
return &insn.text;
}

23
arch/x86/kernel/paravirt.c
View File

@ -58,29 +58,12 @@ static void paravirt_BUG(void)
BUG();
}
struct branch {
unsigned char opcode;
u32 delta;
} __attribute__((packed));
static unsigned paravirt_patch_call(void *insn_buff, const void *target,
unsigned long addr, unsigned len)
{
const int call_len = 5;
struct branch *b = insn_buff;
unsigned long delta = (unsigned long)target - (addr+call_len);
if (len < call_len) {
pr_warn("paravirt: Failed to patch indirect CALL at %ps\n", (void *)addr);
/* Kernel might not be viable if patching fails, bail out: */
BUG_ON(1);
}
b->opcode = 0xe8; /* call */
b->delta = delta;
BUILD_BUG_ON(sizeof(*b) != call_len);
return call_len;
__text_gen_insn(insn_buff, CALL_INSN_OPCODE,
(void *)addr, target, CALL_INSN_SIZE);
return CALL_INSN_SIZE;
}
#ifdef CONFIG_PARAVIRT_XXL