dcdcb9228b
1. Enable this feature only for 32-bit CPUs as MIPS64 can not access the full range unmapped uncached memory. 2. Backport this fix to the 6.1 old LTS kernel. Signed-off-by: Shiji Yang <yangshiji66@qq.com>
75 lines
2.4 KiB
Diff
75 lines
2.4 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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4. Enable this feature only for 32-bit CPUs. Currently, only ath79 and
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ralink CPUs are using 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/include/asm/bootinfo.h | 2 ++
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arch/mips/kernel/setup.c | 17 ++++++++++++-----
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2 files changed, 14 insertions(+), 5 deletions(-)
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--- a/arch/mips/include/asm/bootinfo.h
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+++ b/arch/mips/include/asm/bootinfo.h
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@@ -93,7 +93,9 @@ const char *get_system_type(void);
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extern unsigned long mips_machtype;
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+#ifndef CONFIG_64BIT
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extern void detect_memory_region(phys_addr_t start, phys_addr_t sz_min, phys_addr_t sz_max);
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+#endif
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extern void prom_init(void);
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extern void prom_free_prom_memory(void);
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--- a/arch/mips/kernel/setup.c
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+++ b/arch/mips/kernel/setup.c
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@@ -90,21 +90,27 @@ 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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-
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#ifdef CONFIG_MIPS_AUTO_PFN_OFFSET
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unsigned long ARCH_PFN_OFFSET;
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EXPORT_SYMBOL(ARCH_PFN_OFFSET);
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#endif
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+#ifndef CONFIG_64BIT
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+static u32 detect_magic __initdata;
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+#define MIPS_MEM_TEST_PATTERN 0xaa5555aa
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+
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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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@@ -115,6 +121,7 @@ void __init detect_memory_region(phys_ad
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memblock_add(start, size);
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}
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+#endif /* CONFIG_64BIT */
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/*
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* Manage initrd
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