Messages in this thread Patch in this message | | | Subject | Re: [PATCH] MIPS: relocatable: Provide kaslr_offset() to get the kernel offset | From | Jinyang He <> | Date | Tue, 2 Feb 2021 13:55:25 +0800 |
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On 02/01/2021 08:50 PM, Thomas Bogendoerfer wrote:
> On Wed, Jan 27, 2021 at 12:12:25PM +0800, Jinyang He wrote: >> Use kimage_vaddr to indicate kernel start address. Provide kaslr_offset() >> to get the kernel offset when KASLR is enabled. Error may occur before >> update_kimage_vaddr(), so put it at the end of the offset branch. >> >> Fixes: a307a4ce9ecd ("MIPS: Loongson64: Add KASLR support") >> Reported-by: kernel test robot <lkp@intel.com> >> Signed-off-by: Jinyang He <hejinyang@loongson.cn> >> --- >> arch/mips/include/asm/page.h | 6 ++++++ >> arch/mips/kernel/relocate.c | 12 ++++++++++++ >> arch/mips/kernel/setup.c | 3 +++ >> 3 files changed, 21 insertions(+) >> >> diff --git a/arch/mips/include/asm/page.h b/arch/mips/include/asm/page.h >> index 6a77bc4..9429520 100644 >> --- a/arch/mips/include/asm/page.h >> +++ b/arch/mips/include/asm/page.h >> @@ -255,6 +255,12 @@ extern bool __virt_addr_valid(const volatile void *kaddr); >> >> #define VM_DATA_DEFAULT_FLAGS VM_DATA_FLAGS_TSK_EXEC >> >> +extern unsigned long kimage_vaddr; >> +static inline unsigned long kaslr_offset(void) >> +{ >> + return kimage_vaddr - VMLINUX_LOAD_ADDRESS; >> +} > this breaks for 32bit kernels: > > <command-line>:0:22: error: large integer implicitly truncated to unsigned type [-Werror=overflow] > /local/tbogendoerfer/korg/linux/arch/mips/kernel/setup.c:87:41: note: in expansion of macro ‘VMLINUX_LOAD_ADDRESS’ > unsigned long kimage_vaddr __initdata = VMLINUX_LOAD_ADDRESS; > ^~~~~~~~~~~~~~~~~~~~ > cc1: all warnings being treated as errors >
Sorry for not considering the 32bits kernel. Maybe a variable is enough.
Like this,
diff --git a/arch/mips/include/asm/page.h b/arch/mips/include/asm/page.h index 6a77bc4a6eec..74082e35d57c 100644 --- a/arch/mips/include/asm/page.h +++ b/arch/mips/include/asm/page.h @@ -255,6 +255,12 @@ extern bool __virt_addr_valid(const volatile void *kaddr);
#define VM_DATA_DEFAULT_FLAGS VM_DATA_FLAGS_TSK_EXEC
+extern unsigned long __kaslr_offset; +static inline unsigned long kaslr_offset(void) +{ + return __kaslr_offset; +} + #include <asm-generic/memory_model.h> #include <asm-generic/getorder.h>
diff --git a/arch/mips/kernel/relocate.c b/arch/mips/kernel/relocate.c index c643c816cbe0..95abb9c82f00 100644 --- a/arch/mips/kernel/relocate.c +++ b/arch/mips/kernel/relocate.c @@ -300,6 +300,13 @@ static inline int __init relocation_addr_valid(void *loc_new) return 1; }
+static inline void __init update_kaslr_offset(unsigned long *addr, long offset) +{ + unsigned long *new_addr = (unsigned long *)RELOCATED(addr); + + *new_addr = (unsigned long)offset; +} + #if defined(CONFIG_USE_OF) void __weak *plat_get_fdt(void) { @@ -410,6 +417,9 @@ void *__init relocate_kernel(void)
/* Return the new kernel's entry point */ kernel_entry = RELOCATED(start_kernel); + + /* Error may occur before, so keep it at last */ + update_kaslr_offset(&__kaslr_offset, offset); } out: return kernel_entry; diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c index 7e1f8e277437..cde234326738 100644 --- a/arch/mips/kernel/setup.c +++ b/arch/mips/kernel/setup.c @@ -84,6 +84,9 @@ static struct resource code_resource = { .name = "Kernel code", }; static struct resource data_resource = { .name = "Kernel data", }; static struct resource bss_resource = { .name = "Kernel bss", };
+unsigned long __kaslr_offset __initdata = 0; +EXPORT_SYMBOL(__kaslr_offset); + static void *detect_magic __initdata = detect_memory_region;
#ifdef CONFIG_MIPS_AUTO_PFN_OFFSET I'll send v2 later if no other comment.
Thanks, Jinyang
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