e6d6c071f2
Add the x86 out-of-line static call implementation. For each key, a permanent trampoline is created which is the destination for all static calls for the given key. The trampoline has a direct jump which gets patched by static_call_update() when the destination function changes. [peterz: fixed trampoline, rewrote patching code] Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20200818135804.804315175@infradead.org
32 lines
765 B
C
32 lines
765 B
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/static_call.h>
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#include <linux/memory.h>
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#include <linux/bug.h>
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#include <asm/text-patching.h>
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static void __static_call_transform(void *insn, u8 opcode, void *func)
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{
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const void *code = text_gen_insn(opcode, insn, func);
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if (WARN_ONCE(*(u8 *)insn != opcode,
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"unexpected static call insn opcode 0x%x at %pS\n",
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opcode, insn))
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return;
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if (memcmp(insn, code, CALL_INSN_SIZE) == 0)
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return;
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text_poke_bp(insn, code, CALL_INSN_SIZE, NULL);
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}
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void arch_static_call_transform(void *site, void *tramp, void *func)
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{
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mutex_lock(&text_mutex);
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if (tramp)
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__static_call_transform(tramp, JMP32_INSN_OPCODE, func);
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mutex_unlock(&text_mutex);
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}
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EXPORT_SYMBOL_GPL(arch_static_call_transform);
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