From: Alexander Potapenko <glider@google.com>
Date: Wed, 11 Jan 2023 10:18:06 +0000 (+0100)
Subject: Revert "x86: kmsan: sync metadata pages on page fault"
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=1e15d374bb1cb95f738334018a216e4f6360e821;p=linux.git
Revert "x86: kmsan: sync metadata pages on page fault"
This reverts commit 3f1e2c7a9099c1ed32c67f12cdf432ba782cf51f.
As noticed by Qun-Wei Lin, arch_sync_kernel_mappings() in
arch/x86/mm/fault.c is only used with CONFIG_X86_32, whereas KMSAN is only
supported on x86_64, where this code is not compiled.
The patch in question dates back to downstream KMSAN branch based on
v5.8-rc5, it sneaked into upstream unnoticed in v6.1.
Link: https://lkml.kernel.org/r/20230111101806.3236991-1-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Reported-by: Qun-Wei Lin <qun-wei.lin@mediatek.com>
Link: https://github.com/google/kmsan/issues/91
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Marco Elver <elver@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 7b0d4ab894c8b..a498ae1fbe665 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -260,7 +260,7 @@ static noinline int vmalloc_fault(unsigned long address)
}
NOKPROBE_SYMBOL(vmalloc_fault);
-static void __arch_sync_kernel_mappings(unsigned long start, unsigned long end)
+void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
{
unsigned long addr;
@@ -284,27 +284,6 @@ static void __arch_sync_kernel_mappings(unsigned long start, unsigned long end)
}
}
-void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
-{
- __arch_sync_kernel_mappings(start, end);
-#ifdef CONFIG_KMSAN
- /*
- * KMSAN maintains two additional metadata page mappings for the
- * [VMALLOC_START, VMALLOC_END) range. These mappings start at
- * KMSAN_VMALLOC_SHADOW_START and KMSAN_VMALLOC_ORIGIN_START and
- * have to be synced together with the vmalloc memory mapping.
- */
- if (start >= VMALLOC_START && end < VMALLOC_END) {
- __arch_sync_kernel_mappings(
- start - VMALLOC_START + KMSAN_VMALLOC_SHADOW_START,
- end - VMALLOC_START + KMSAN_VMALLOC_SHADOW_START);
- __arch_sync_kernel_mappings(
- start - VMALLOC_START + KMSAN_VMALLOC_ORIGIN_START,
- end - VMALLOC_START + KMSAN_VMALLOC_ORIGIN_START);
- }
-#endif
-}
-
static bool low_pfn(unsigned long pfn)
{
return pfn < max_low_pfn;