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generic: fix detect_memory_region() function

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This patch fixes the broken detect_memory_region() function on
6.6 kernel.

Signed-off-by: Shiji Yang <yangshiji66@qq.com>
This commit is contained in:
Shiji Yang 2024-03-14 03:39:01 +08:00 committed by Nick Hainke
parent 7753b143cd
commit c5dee97d87
1 changed files with 56 additions and 0 deletions
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56
target/linux/generic/pending-6.6/350-mips-kernel-fix-detect_memory_region-function.patch Normal file
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@ -0,0 +1,56 @@
From: Shiji Yang <yangshiji66@outlook.com>
Date: Wed, 13 Mar 2024 20:28:37 +0800
Subject: [PATCH] mips: kernel: fix detect_memory_region() function
1. Do not use memcmp() on unallocated memory, as the new introduced
fortify dynamic object size check[1] will report unexpected result.
2. Use a fixed pattern instead of a random function pointer as the
magic value.
3. Flip magic value and double check it.
[1] 439a1bcac648 ("fortify: Use __builtin_dynamic_object_size() when available")
Signed-off-by: Shiji Yang <yangshiji66@outlook.com>
---
arch/mips/kernel/setup.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -46,6 +46,8 @@
#include <asm/prom.h>
#include <asm/fw/fw.h>
+#define MIPS_MEM_TEST_PATTERN 0xaa5555aa
+
#ifdef CONFIG_MIPS_ELF_APPENDED_DTB
char __section(".appended_dtb") __appended_dtb[0x100000];
#endif /* CONFIG_MIPS_ELF_APPENDED_DTB */
@@ -90,7 +92,7 @@ static struct resource bss_resource = {
unsigned long __kaslr_offset __ro_after_init;
EXPORT_SYMBOL(__kaslr_offset);
-static void *detect_magic __initdata = detect_memory_region;
+static u32 detect_magic __initdata;
#ifdef CONFIG_MIPS_AUTO_PFN_OFFSET
unsigned long ARCH_PFN_OFFSET;
@@ -99,12 +101,16 @@ EXPORT_SYMBOL(ARCH_PFN_OFFSET);
void __init detect_memory_region(phys_addr_t start, phys_addr_t sz_min, phys_addr_t sz_max)
{
- void *dm = &detect_magic;
+ void *dm = (void *)KSEG1ADDR(&detect_magic);
phys_addr_t size;
for (size = sz_min; size < sz_max; size <<= 1) {
- if (!memcmp(dm, dm + size, sizeof(detect_magic)))
- break;
+ __raw_writel(MIPS_MEM_TEST_PATTERN, dm);
+ if (__raw_readl(dm) == __raw_readl(dm + size)) {
+ __raw_writel(~MIPS_MEM_TEST_PATTERN, dm);
+ if (__raw_readl(dm) == __raw_readl(dm + size))
+ break;
+ }
}
pr_debug("Memory: %lluMB of RAM detected at 0x%llx (min: %lluMB, max: %lluMB)\n",