From 6becb5026b8192e0ed6619d6e7793c2f1288244f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 8 Feb 2023 18:10:51 +0100 Subject: [PATCH] x86/alternative: Make debug-alternative selective Using debug-alternative generates a *LOT* of output, extend it a bit to select which of the many rewrites it reports on. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20230208171431.253636689@infradead.org --- arch/x86/kernel/alternative.c | 62 +++++++++++++++++++++-------------- 1 file changed, 37 insertions(+), 25 deletions(-) diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index f615e0cb6d93..b3ae6cfa92f4 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -37,11 +37,23 @@ EXPORT_SYMBOL_GPL(alternatives_patched); #define MAX_PATCH_LEN (255-1) -static int __initdata_or_module debug_alternative; +#define DA_ALL (~0) +#define DA_ALT 0x01 +#define DA_RET 0x02 +#define DA_RETPOLINE 0x04 +#define DA_ENDBR 0x08 +#define DA_SMP 0x10 + +static unsigned int __initdata_or_module debug_alternative; static int __init debug_alt(char *str) { - debug_alternative = 1; + if (str && *str == '=') + str++; + + if (!str || kstrtouint(str, 0, &debug_alternative)) + debug_alternative = DA_ALL; + return 1; } __setup("debug-alternative", debug_alt); @@ -55,15 +67,15 @@ static int __init setup_noreplace_smp(char *str) } __setup("noreplace-smp", setup_noreplace_smp); -#define DPRINTK(fmt, args...) \ +#define DPRINTK(type, fmt, args...) \ do { \ - if (debug_alternative) \ + if (debug_alternative & DA_##type) \ printk(KERN_DEBUG pr_fmt(fmt) "\n", ##args); \ } while (0) -#define DUMP_BYTES(buf, len, fmt, args...) \ +#define DUMP_BYTES(type, buf, len, fmt, args...) \ do { \ - if (unlikely(debug_alternative)) { \ + if (unlikely(debug_alternative & DA_##type)) { \ int j; \ \ if (!(len)) \ @@ -148,7 +160,7 @@ recompute_jump(struct alt_instr *a, u8 *orig_insn, u8 *repl_insn, u8 *insn_buff) tgt_rip = next_rip + o_dspl; n_dspl = tgt_rip - orig_insn; - DPRINTK("target RIP: %px, new_displ: 0x%x", tgt_rip, n_dspl); + DPRINTK(ALT, "target RIP: %px, new_displ: 0x%x", tgt_rip, n_dspl); if (tgt_rip - orig_insn >= 0) { if (n_dspl - 2 <= 127) @@ -183,7 +195,7 @@ five_byte_jmp: done: - DPRINTK("final displ: 0x%08x, JMP 0x%lx", + DPRINTK(ALT, "final displ: 0x%08x, JMP 0x%lx", n_dspl, (unsigned long)orig_insn + n_dspl + repl_len); } @@ -217,7 +229,7 @@ static __always_inline int optimize_nops_range(u8 *instr, u8 instrlen, int off) add_nops(instr + off, nnops); local_irq_restore(flags); - DUMP_BYTES(instr, instrlen, "%px: [%d:%d) optimized NOPs: ", instr, off, i); + DUMP_BYTES(ALT, instr, instrlen, "%px: [%d:%d) optimized NOPs: ", instr, off, i); return nnops; } @@ -270,7 +282,7 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start, u8 *instr, *replacement; u8 insn_buff[MAX_PATCH_LEN]; - DPRINTK("alt table %px, -> %px", start, end); + DPRINTK(ALT, "alt table %px, -> %px", start, end); /* * The scan order should be from start to end. A later scanned * alternative code can overwrite previously scanned alternative code. @@ -297,15 +309,15 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start, if (!boot_cpu_has(a->cpuid) == !(a->flags & ALT_FLAG_NOT)) goto next; - DPRINTK("feat: %s%d*32+%d, old: (%pS (%px) len: %d), repl: (%px, len: %d)", + DPRINTK(ALT, "feat: %s%d*32+%d, old: (%pS (%px) len: %d), repl: (%px, len: %d)", (a->flags & ALT_FLAG_NOT) ? "!" : "", a->cpuid >> 5, a->cpuid & 0x1f, instr, instr, a->instrlen, replacement, a->replacementlen); - DUMP_BYTES(instr, a->instrlen, "%px: old_insn: ", instr); - DUMP_BYTES(replacement, a->replacementlen, "%px: rpl_insn: ", replacement); + DUMP_BYTES(ALT, instr, a->instrlen, "%px: old_insn: ", instr); + DUMP_BYTES(ALT, replacement, a->replacementlen, "%px: rpl_insn: ", replacement); memcpy(insn_buff, replacement, a->replacementlen); insn_buff_sz = a->replacementlen; @@ -318,7 +330,7 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start, */ if (a->replacementlen == 5 && *insn_buff == 0xe8) { *(s32 *)(insn_buff + 1) += replacement - instr; - DPRINTK("Fix CALL offset: 0x%x, CALL 0x%lx", + DPRINTK(ALT, "Fix CALL offset: 0x%x, CALL 0x%lx", *(s32 *)(insn_buff + 1), (unsigned long)instr + *(s32 *)(insn_buff + 1) + 5); } @@ -329,7 +341,7 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start, for (; insn_buff_sz < a->instrlen; insn_buff_sz++) insn_buff[insn_buff_sz] = 0x90; - DUMP_BYTES(insn_buff, insn_buff_sz, "%px: final_insn: ", instr); + DUMP_BYTES(ALT, insn_buff, insn_buff_sz, "%px: final_insn: ", instr); text_poke_early(instr, insn_buff, insn_buff_sz); @@ -555,15 +567,15 @@ void __init_or_module noinline apply_retpolines(s32 *start, s32 *end) continue; } - DPRINTK("retpoline at: %pS (%px) len: %d to: %pS", + DPRINTK(RETPOLINE, "retpoline at: %pS (%px) len: %d to: %pS", addr, addr, insn.length, addr + insn.length + insn.immediate.value); len = patch_retpoline(addr, &insn, bytes); if (len == insn.length) { optimize_nops(bytes, len); - DUMP_BYTES(((u8*)addr), len, "%px: orig: ", addr); - DUMP_BYTES(((u8*)bytes), len, "%px: repl: ", addr); + DUMP_BYTES(RETPOLINE, ((u8*)addr), len, "%px: orig: ", addr); + DUMP_BYTES(RETPOLINE, ((u8*)bytes), len, "%px: repl: ", addr); text_poke_early(addr, bytes, len); } } @@ -630,14 +642,14 @@ void __init_or_module noinline apply_returns(s32 *start, s32 *end) addr, dest, 5, addr)) continue; - DPRINTK("return thunk at: %pS (%px) len: %d to: %pS", + DPRINTK(RET, "return thunk at: %pS (%px) len: %d to: %pS", addr, addr, insn.length, addr + insn.length + insn.immediate.value); len = patch_return(addr, &insn, bytes); if (len == insn.length) { - DUMP_BYTES(((u8*)addr), len, "%px: orig: ", addr); - DUMP_BYTES(((u8*)bytes), len, "%px: repl: ", addr); + DUMP_BYTES(RET, ((u8*)addr), len, "%px: orig: ", addr); + DUMP_BYTES(RET, ((u8*)bytes), len, "%px: repl: ", addr); text_poke_early(addr, bytes, len); } } @@ -667,13 +679,13 @@ static void poison_endbr(void *addr, bool warn) return; } - DPRINTK("ENDBR at: %pS (%px)", addr, addr); + DPRINTK(ENDBR, "ENDBR at: %pS (%px)", addr, addr); /* * When we have IBT, the lack of ENDBR will trigger #CP */ - DUMP_BYTES(((u8*)addr), 4, "%px: orig: ", addr); - DUMP_BYTES(((u8*)&poison), 4, "%px: repl: ", addr); + DUMP_BYTES(ENDBR, ((u8*)addr), 4, "%px: orig: ", addr); + DUMP_BYTES(ENDBR, ((u8*)&poison), 4, "%px: repl: ", addr); text_poke_early(addr, &poison, 4); } @@ -1148,7 +1160,7 @@ void __init_or_module alternatives_smp_module_add(struct module *mod, smp->locks_end = locks_end; smp->text = text; smp->text_end = text_end; - DPRINTK("locks %p -> %p, text %p -> %p, name %s\n", + DPRINTK(SMP, "locks %p -> %p, text %p -> %p, name %s\n", smp->locks, smp->locks_end, smp->text, smp->text_end, smp->name); -- 2.20.1