add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/arch/x86/kernel/static_call.c
..
..
@@ -123,6 +123,19 @@
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  */
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 bool __static_call_fixup(void *tramp, u8 op, void *dest)
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 {
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+	unsigned long addr = (unsigned long)tramp;
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+	/*
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+	 * Not all .return_sites are a static_call trampoline (most are not).
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+	 * Check if the 3 bytes after the return are still kernel text, if not,
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+	 * then this definitely is not a trampoline and we need not worry
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+	 * further.
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+	 *
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+	 * This avoids the memcmp() below tripping over pagefaults etc..
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+	 */
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+	if (((addr >> PAGE_SHIFT) != ((addr + 7) >> PAGE_SHIFT)) &&
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+	    !kernel_text_address(addr + 7))
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+		return false;
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+
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 	if (memcmp(tramp+5, tramp_ud, 3)) {
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 		/* Not a trampoline site, not our problem. */
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 		return false;