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

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Upstream commit: ba27d1a80871eb8dbeddf34ec7d396c149cbb8d7

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
 [ Keep struct branch. ]
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 e752912ce1
commit b253061d4b
2 changed files with 19 additions and 23 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 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 */ union text_poke_insn *insn = buf;
int size = text_opcode_size(opcode);
BUG_ON(size < text_opcode_size(opcode));
/* /*
* Hide the addresses to avoid the compiler folding in constants when * Hide the addresses to avoid the compiler folding in constants when
* referencing code, these can mess up annotations like * referencing code, these can mess up annotations like
* ANNOTATE_NOENDBR. * ANNOTATE_NOENDBR.
*/ */
OPTIMIZER_HIDE_VAR(insn);
OPTIMIZER_HIDE_VAR(addr); OPTIMIZER_HIDE_VAR(addr);
OPTIMIZER_HIDE_VAR(dest); OPTIMIZER_HIDE_VAR(dest);
insn.opcode = opcode; insn->opcode = opcode;
if (size > 1) { if (size > 1) {
insn.disp = (long)dest - (long)(addr + size); insn->disp = (long)dest - (long)(addr + size);
if (size == 2) { if (size == 2) {
/* /*
* Ensure that for JMP8 the displacement * Ensure that for JMP8 the displacement
* actually fits the signed byte. * 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; return &insn.text;
} }

22
arch/x86/kernel/paravirt.c
View File

@ -55,28 +55,16 @@ void __init default_banner(void)
static const unsigned char ud2a[] = { 0x0f, 0x0b }; static const unsigned char ud2a[] = { 0x0f, 0x0b };
struct branch { struct branch {
unsigned char opcode; unsigned char opcode;
u32 delta; u32 delta;
} __attribute__((packed)); } __attribute__((packed));
static unsigned paravirt_patch_call(void *insn_buff, const void *target, static unsigned paravirt_patch_call(void *insn_buff, const void *target,
unsigned long addr, unsigned len) unsigned long addr, unsigned len)
{ {
const int call_len = 5; __text_gen_insn(insn_buff, CALL_INSN_OPCODE,
struct branch *b = insn_buff; (void *)addr, target, CALL_INSN_SIZE);
unsigned long delta = (unsigned long)target - (addr+call_len); return CALL_INSN_SIZE;
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;
} }
#ifdef CONFIG_PARAVIRT_XXL #ifdef CONFIG_PARAVIRT_XXL