1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
|
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.
4. Enable this feature only for 32-bit CPUs. Currently, only ath79 and
ralink CPUs are using it.
[1] 439a1bcac648 ("fortify: Use __builtin_dynamic_object_size() when available")
Signed-off-by: Shiji Yang <yangshiji66@outlook.com>
---
arch/mips/include/asm/bootinfo.h | 2 ++
arch/mips/kernel/setup.c | 17 ++++++++++++-----
2 files changed, 14 insertions(+), 5 deletions(-)
--- a/arch/mips/include/asm/bootinfo.h
+++ b/arch/mips/include/asm/bootinfo.h
@@ -93,7 +93,9 @@ const char *get_system_type(void);
extern unsigned long mips_machtype;
+#ifndef CONFIG_64BIT
extern void detect_memory_region(phys_addr_t start, phys_addr_t sz_min, phys_addr_t sz_max);
+#endif
extern void prom_init(void);
extern void prom_free_prom_memory(void);
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -90,21 +90,27 @@ static struct resource bss_resource = {
unsigned long __kaslr_offset __ro_after_init;
EXPORT_SYMBOL(__kaslr_offset);
-static void *detect_magic __initdata = detect_memory_region;
-
#ifdef CONFIG_MIPS_AUTO_PFN_OFFSET
unsigned long ARCH_PFN_OFFSET;
EXPORT_SYMBOL(ARCH_PFN_OFFSET);
#endif
+#ifndef CONFIG_64BIT
+static u32 detect_magic __initdata;
+#define MIPS_MEM_TEST_PATTERN 0xaa5555aa
+
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",
@@ -115,6 +121,7 @@ void __init detect_memory_region(phys_ad
memblock_add(start, size);
}
+#endif /* CONFIG_64BIT */
/*
* Manage initrd
|
