Messages in this thread Patch in this message | | | Date | Thu, 3 May 2018 13:52:05 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH] x86/boot/compressed: Exclude 'top_pgtable' from relocation |
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On Thu, May 03, 2018 at 08:38:49AM +0000, Kirill A. Shutemov wrote: > The patch is bogus and I still don't understand what is going on.
I think I found the issue. Could you check the patch below:
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index fca012baba19..86169ae1c536 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -370,10 +370,13 @@ trampoline_return: /* * cleanup_trampoline() would restore trampoline memory. * + * RDI is address of the page table to use (if required). + * * RSI holds real mode data and needs to be preserved across * this function call. */ pushq %rsi + leaq top_pgtable(%rbx), %rdi call cleanup_trampoline popq %rsi @@ -647,5 +650,14 @@ boot_stack_end: */ .section ".pgtable","a",@nobits .balign 4096 + .global pgtable pgtable: .fill BOOT_PGT_SIZE, 1, 0 + +/* + * The page table is going to be used instead of page table in the trampoline + * memory. + */ + .global top_pgtable +top_pgtable: + .fill PAGE_SIZE, 1, 0 diff --git a/arch/x86/boot/compressed/pgtable_64.c b/arch/x86/boot/compressed/pgtable_64.c index 32af1cbcd903..a362fa0b849c 100644 --- a/arch/x86/boot/compressed/pgtable_64.c +++ b/arch/x86/boot/compressed/pgtable_64.c @@ -22,14 +22,6 @@ struct paging_config { /* Buffer to preserve trampoline memory */ static char trampoline_save[TRAMPOLINE_32BIT_SIZE]; -/* - * The page table is going to be used instead of page table in the trampoline - * memory. - * - * It must not be in BSS as BSS is cleared after cleanup_trampoline(). - */ -static char top_pgtable[PAGE_SIZE] __aligned(PAGE_SIZE) __section(.data); - /* * Trampoline address will be printed by extract_kernel() for debugging * purposes. @@ -134,7 +126,7 @@ struct paging_config paging_prepare(void) return paging_config; } -void cleanup_trampoline(void) +void cleanup_trampoline(void *pgtable) { void *trampoline_pgtable; @@ -145,8 +137,8 @@ void cleanup_trampoline(void) * if it's there. */ if ((void *)__native_read_cr3() == trampoline_pgtable) { - memcpy(top_pgtable, trampoline_pgtable, PAGE_SIZE); - native_write_cr3((unsigned long)top_pgtable); + memcpy(pgtable, trampoline_pgtable, PAGE_SIZE); + native_write_cr3((unsigned long)pgtable); } /* Restore trampoline memory */ -- Kirill A. Shutemov
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