Messages in this thread | | | Subject | Re: [PATCH] LoongArch: Add kernel address sanitizer support | From | Qing Zhang <> | Date | Tue, 28 Mar 2023 20:15:33 +0800 |
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Hi, Ruoyao
On 2023/3/28 下午7:39, Xi Ruoyao wrote: > On Tue, 2023-03-28 at 19:17 +0800, Qing Zhang wrote: > > /* snip */ > > >> -void * __init relocate_kernel(void) >> +unsigned long __init relocate_kernel(void) > > Why we must modify relocate_kernel for KASAN?
When the CONFIG_RANDOMIZE_BASE is enabled, the kernel will be updated to a random new address. Kasan needs to call kasan_early_init before start_kernel. There are two situations: 1> After enabling CONFIG_RELOCATABLE, call kasan_early_init. 2> After CONFIG_RELOCATABLE is not enabled, call kasan_early_init.
In order to prevent code redundancy and semantic problems caused by calling kasan_early_init (before jr a0) at the old PC.
Thanks, -Qing > >> { >> unsigned long kernel_length; >> unsigned long random_offset = 0; >> void *location_new = _text; /* Default to original kernel start */ >> - void *kernel_entry = start_kernel; /* Default to original kernel entry point */ >> char *cmdline = early_ioremap(fw_arg1, COMMAND_LINE_SIZE); /* Boot command line is passed in fw_arg1 */ >> >> strscpy(boot_command_line, cmdline, COMMAND_LINE_SIZE); >> @@ -190,9 +189,6 @@ void * __init relocate_kernel(void) >> >> reloc_offset += random_offset; >> >> - /* Return the new kernel's entry point */ >> - kernel_entry = RELOCATED_KASLR(start_kernel); >> - >> /* The current thread is now within the relocated kernel */ >> __current_thread_info = RELOCATED_KASLR(__current_thread_info); >> >> @@ -204,7 +200,7 @@ void * __init relocate_kernel(void) >> >> relocate_absolute(random_offset); >> >> - return kernel_entry; >> + return random_offset; >
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