50 lines
1.8 KiB
Diff
50 lines
1.8 KiB
Diff
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From 6392262b68387299ee81d5d659cb5423a2ae1c9c Mon Sep 17 00:00:00 2001
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From: Michal Kubecek <mkubecek@suse.cz>
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Date: Mon, 26 Mar 2018 13:33:32 +0200
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Subject: [PATCH 09/10] vmmon: fix indirect call with retpoline build
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Build against kernel with retpoline support issues warning
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objtool: Task_Switch()+0x425: indirect call found in RETPOLINE build
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This is because an indirect call in TaskSwitchToMonitor() is encoded using
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inline assembler so that it bypasses retpoline generation. For this
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purpose, macro CALL_NOSPEC exists since v4.15-rc8 (and has been backported
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into some distribution kernels with the rest of retpoline support). Use the
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macro if available and fallback to the original code if not.
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---
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vmmon-only/common/task.c | 11 +++++++++++
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1 file changed, 11 insertions(+)
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diff --git a/vmmon-only/common/task.c b/vmmon-only/common/task.c
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index 98cc74a..400ebfe 100644
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--- a/vmmon-only/common/task.c
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+++ b/vmmon-only/common/task.c
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@@ -2203,12 +2203,23 @@ TaskSwitchToMonitor(VMCrossPage *crosspage)
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{
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uint64 raxGetsWiped, rcxGetsWiped;
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+#ifdef CALL_NOSPEC
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+ __asm__ __volatile__(CALL_NOSPEC
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+ : "=a" (raxGetsWiped),
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+ "=c" (rcxGetsWiped)
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+ : "0" (codePtr),
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+ "1" (crosspage),
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+ THUNK_TARGET(codePtr)
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+ : "rdx", "r8", "r9", "r10", "r11", "cc", "memory");
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+#else
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__asm__ __volatile__("call *%%rax"
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: "=a" (raxGetsWiped),
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"=c" (rcxGetsWiped)
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: "0" (codePtr),
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"1" (crosspage)
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: "rdx", "r8", "r9", "r10", "r11", "cc", "memory");
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+#endif
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+
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}
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#elif defined(_MSC_VER)
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/*
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--
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2.17.0
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