Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'locking-urgent-2021-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 static call update from Thomas Gleixner:
"A single fix for static calls to make the trampoline patching more
robust by placing explicit signature bytes after the call trampoline
to prevent patching random other jumps like the CFI jump table
entries"
* tag 'locking-urgent-2021-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
static_call,x86: Robustify trampoline patching
+14
-4
+1
arch/x86/include/asm/static_call.h
+1
arch/x86/include/asm/static_call.h
···
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".globl " STATIC_CALL_TRAMP_STR(name) " \n" \
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STATIC_CALL_TRAMP_STR(name) ": \n" \
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insns " \n" \
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+
".byte 0x53, 0x43, 0x54 \n" \
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".type " STATIC_CALL_TRAMP_STR(name) ", @function \n" \
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".size " STATIC_CALL_TRAMP_STR(name) ", . - " STATIC_CALL_TRAMP_STR(name) " \n" \
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".popsection \n")
+10
-4
arch/x86/kernel/static_call.c
+10
-4
arch/x86/kernel/static_call.c
···
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text_poke_bp(insn, code, size, emulate);
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}
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-
static void __static_call_validate(void *insn, bool tail)
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+
static void __static_call_validate(void *insn, bool tail, bool tramp)
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{
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u8 opcode = *(u8 *)insn;
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+
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+
if (tramp && memcmp(insn+5, "SCT", 3)) {
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+
pr_err("trampoline signature fail");
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+
BUG();
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+
}
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if (tail) {
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if (opcode == JMP32_INSN_OPCODE ||
···
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/*
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* If we ever trigger this, our text is corrupt, we'll probably not live long.
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*/
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-
WARN_ONCE(1, "unexpected static_call insn opcode 0x%x at %pS\n", opcode, insn);
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+
pr_err("unexpected static_call insn opcode 0x%x at %pS\n", opcode, insn);
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+
BUG();
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}
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static inline enum insn_type __sc_insn(bool null, bool tail)
···
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mutex_lock(&text_mutex);
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if (tramp) {
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-
__static_call_validate(tramp, true);
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+
__static_call_validate(tramp, true, true);
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__static_call_transform(tramp, __sc_insn(!func, true), func);
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}
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if (IS_ENABLED(CONFIG_HAVE_STATIC_CALL_INLINE) && site) {
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-
__static_call_validate(site, tail);
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+
__static_call_validate(site, tail, false);
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__static_call_transform(site, __sc_insn(!func, tail), func);
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}
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+3
tools/objtool/check.c
+3
tools/objtool/check.c