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