在2024年6月25日六月 上午2:44，Shiji Yang写道： > The detect_memory_region() has been broken on 6.6 kernel[1]. This > patch fixes it by: > 1. Do not use memcmp() on unallocated memory, as the new introduced > fortify dynamic object size check[2] will return 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. And 64-bit CPU doesn't have the KSEG1ADDR > definition. Hi Shiji, Thanks for your patch. Please don't break 64bit system. Use CKSEG1ADDR_OR_64BIT instead. Thanks - Jiaxun > > [1] > https://github.com/openwrt/openwrt/pull/14774#issuecomment-1989356746 > [2] commit 439a1bcac648 ("fortify: Use __builtin_dynamic_object_size() > when available") > Signed-off-by: Shiji Yang <yangshiji66@xxxxxxxxxxx> > Tested-by: Mieczyslaw Nalewaj <namiltd@xxxxxxxxx> > --- > arch/mips/include/asm/bootinfo.h | 2 ++ > arch/mips/kernel/setup.c | 17 ++++++++++++----- > 2 files changed, 14 insertions(+), 5 deletions(-) > > diff --git a/arch/mips/include/asm/bootinfo.h b/arch/mips/include/asm/bootinfo.h > index 2128ba903391..8516c11916a4 100644 > --- 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); > diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c > index 12a1a4ffb602..3a3bc1b7e62e 100644 > --- a/arch/mips/kernel/setup.c > +++ b/arch/mips/kernel/setup.c > @@ -86,21 +86,27 @@ static struct resource bss_resource = { .name = > "Kernel bss", }; > 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", > @@ -111,6 +117,7 @@ void __init detect_memory_region(phys_addr_t start, > phys_addr_t sz_min, phys_add > > memblock_add(start, size); > } > +#endif /* CONFIG_64BIT */ > > /* > * Manage initrd > -- > 2.45.1 -- - Jiaxun
