5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Upstream commit: ba27d1a80871eb8dbeddf34ec7d396c149cbb8d7 Less duplication is more better. Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Link: https://lore.kernel.org/r/20220308154317.697253958@xxxxxxxxxxxxx [ Keep struct branch. ] Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/include/asm/text-patching.h | 20 ++++++++++++++------ arch/x86/kernel/paravirt.c | 22 +++++----------------- 2 files changed, 19 insertions(+), 23 deletions(-) --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -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; } --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -55,28 +55,16 @@ void __init default_banner(void) static const unsigned char ud2a[] = { 0x0f, 0x0b }; struct branch { - unsigned char opcode; - u32 delta; + 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
