* [PATCH] MIPS: relocatable: Provide kaslr_offset() to get the kernel offset
@ 2021-01-27 4:12 Jinyang He
2021-02-01 12:50 ` Thomas Bogendoerfer
0 siblings, 1 reply; 3+ messages in thread
From: Jinyang He @ 2021-01-27 4:12 UTC (permalink / raw)
To: Thomas Bogendoerfer; +Cc: Huacai Chen, Jiaxun Yang, linux-mips, linux-kernel
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;
+}
+
#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 c643c81..2cbc3b1 100644
--- a/arch/mips/kernel/relocate.c
+++ b/arch/mips/kernel/relocate.c
@@ -300,6 +300,15 @@ static inline int __init relocation_addr_valid(void *loc_new)
return 1;
}
+static inline void __init update_kimage_vaddr(unsigned long value,
+ unsigned long *addr, long offset)
+{
+ unsigned long new_value = value + offset;
+ unsigned long *new_addr = (void *)addr + offset;
+
+ *new_addr = new_value;
+}
+
#if defined(CONFIG_USE_OF)
void __weak *plat_get_fdt(void)
{
@@ -410,6 +419,9 @@ 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_kimage_vaddr(kimage_vaddr, &kimage_vaddr, offset);
}
out:
return kernel_entry;
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 7e1f8e2..ad37b24 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 kimage_vaddr __initdata = VMLINUX_LOAD_ADDRESS;
+EXPORT_SYMBOL(kimage_vaddr);
+
static void *detect_magic __initdata = detect_memory_region;
#ifdef CONFIG_MIPS_AUTO_PFN_OFFSET
--
2.1.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] MIPS: relocatable: Provide kaslr_offset() to get the kernel offset
2021-01-27 4:12 [PATCH] MIPS: relocatable: Provide kaslr_offset() to get the kernel offset Jinyang He
@ 2021-02-01 12:50 ` Thomas Bogendoerfer
2021-02-02 5:55 ` Jinyang He
0 siblings, 1 reply; 3+ messages in thread
From: Thomas Bogendoerfer @ 2021-02-01 12:50 UTC (permalink / raw)
To: Jinyang He; +Cc: Huacai Chen, Jiaxun Yang, linux-mips, linux-kernel
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
--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] MIPS: relocatable: Provide kaslr_offset() to get the kernel offset
2021-02-01 12:50 ` Thomas Bogendoerfer
@ 2021-02-02 5:55 ` Jinyang He
0 siblings, 0 replies; 3+ messages in thread
From: Jinyang He @ 2021-02-02 5:55 UTC (permalink / raw)
To: Thomas Bogendoerfer; +Cc: Huacai Chen, Jiaxun Yang, linux-mips, linux-kernel
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
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2021-01-27 4:12 [PATCH] MIPS: relocatable: Provide kaslr_offset() to get the kernel offset Jinyang He
2021-02-01 12:50 ` Thomas Bogendoerfer
2021-02-02 5:55 ` Jinyang He
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