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x86/ibt: Clean up is_endbr()

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Pretty much every caller of is_endbr() actually wants to test something at an
address and ends up doing get_kernel_nofault(). Fold the lot into a more
convenient helper.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20250207122546.181367417@infradead.org
This commit is contained in:
Peter Zijlstra
2025-02-07 13:15:31 +01:00
parent 92d2da37fd
commit 72e213a7cc
7 changed files with 27 additions and 52 deletions
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16
arch/x86/include/asm/ftrace.h
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@@ -36,21 +36,9 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
static inline unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip)
{
#ifdef CONFIG_X86_KERNEL_IBT
u32 instr;
/* We want to be extra safe in case entry ip is on the page edge,
* but otherwise we need to avoid get_kernel_nofault()'s overhead.
*/
if ((fentry_ip & ~PAGE_MASK) < ENDBR_INSN_SIZE) {
if (get_kernel_nofault(instr, (u32 *)(fentry_ip - ENDBR_INSN_SIZE)))
return fentry_ip;
} else {
instr = *(u32 *)(fentry_ip - ENDBR_INSN_SIZE);
}
if (is_endbr(instr))
if (is_endbr((void*)(fentry_ip - ENDBR_INSN_SIZE)))
fentry_ip -= ENDBR_INSN_SIZE;
#endif
return fentry_ip;
}
#define ftrace_get_symaddr(fentry_ip) arch_ftrace_get_symaddr(fentry_ip)