From 4b47cdbda6f1ad73b08dc7d497bac12b8f26ae0d Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Mon, 7 Sep 2020 15:15:36 +0200 Subject: [PATCH] x86/head/64: Move early exception dispatch to C code Move the assembly coded dispatch between page-faults and all other exceptions to C code to make it easier to maintain and extend. Also change the return-type of early_make_pgtable() to bool and make it static. Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20200907131613.12703-36-joro@8bytes.org --- arch/x86/include/asm/pgtable.h | 2 +- arch/x86/include/asm/setup.h | 4 +++- arch/x86/kernel/head64.c | 19 +++++++++++++++---- arch/x86/kernel/head_64.S | 11 +---------- 4 files changed, 20 insertions(+), 16 deletions(-) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index b836138..7b8f212 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -28,7 +28,7 @@ #include extern pgd_t early_top_pgt[PTRS_PER_PGD]; -int __init __early_make_pgtable(unsigned long address, pmdval_t pmd); +bool __init __early_make_pgtable(unsigned long address, pmdval_t pmd); void ptdump_walk_pgd_level(struct seq_file *m, struct mm_struct *mm); void ptdump_walk_pgd_level_debugfs(struct seq_file *m, struct mm_struct *mm, diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h index 4b3ca5a..7d7a064 100644 --- a/arch/x86/include/asm/setup.h +++ b/arch/x86/include/asm/setup.h @@ -39,6 +39,8 @@ void vsmp_init(void); static inline void vsmp_init(void) { } #endif +struct pt_regs; + void setup_bios_corruption_check(void); void early_platform_quirks(void); @@ -49,8 +51,8 @@ extern void i386_reserve_resources(void); extern unsigned long __startup_64(unsigned long physaddr, struct boot_params *bp); extern unsigned long __startup_secondary_64(void); extern void startup_64_setup_env(unsigned long physbase); -extern int early_make_pgtable(unsigned long address); extern void early_setup_idt(void); +extern void __init do_early_exception(struct pt_regs *regs, int trapnr); #ifdef CONFIG_X86_INTEL_MID extern void x86_intel_mid_early_setup(void); diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 7bfd5c2..4282dac 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -38,6 +38,8 @@ #include #include #include +#include +#include /* * Manage page tables very early on. @@ -317,7 +319,7 @@ static void __init reset_early_page_tables(void) } /* Create a new PMD entry */ -int __init __early_make_pgtable(unsigned long address, pmdval_t pmd) +bool __init __early_make_pgtable(unsigned long address, pmdval_t pmd) { unsigned long physaddr = address - __PAGE_OFFSET; pgdval_t pgd, *pgd_p; @@ -327,7 +329,7 @@ int __init __early_make_pgtable(unsigned long address, pmdval_t pmd) /* Invalid address or early pgt is done ? */ if (physaddr >= MAXMEM || read_cr3_pa() != __pa_nodebug(early_top_pgt)) - return -1; + return false; again: pgd_p = &early_top_pgt[pgd_index(address)].pgd; @@ -384,10 +386,10 @@ again: } pmd_p[pmd_index(address)] = pmd; - return 0; + return true; } -int __init early_make_pgtable(unsigned long address) +static bool __init early_make_pgtable(unsigned long address) { unsigned long physaddr = address - __PAGE_OFFSET; pmdval_t pmd; @@ -397,6 +399,15 @@ int __init early_make_pgtable(unsigned long address) return __early_make_pgtable(address, pmd); } +void __init do_early_exception(struct pt_regs *regs, int trapnr) +{ + if (trapnr == X86_TRAP_PF && + early_make_pgtable(native_read_cr2())) + return; + + early_fixup_exception(regs, trapnr); +} + /* Don't add a printk in there. printk relies on the PDA which is not initialized yet. */ static void __init clear_bss(void) diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 1de09b5..3b40ec4 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -341,18 +341,9 @@ SYM_CODE_START_LOCAL(early_idt_handler_common) pushq %r15 /* pt_regs->r15 */ UNWIND_HINT_REGS - cmpq $14,%rsi /* Page fault? */ - jnz 10f - GET_CR2_INTO(%rdi) /* can clobber %rax if pv */ - call early_make_pgtable - andl %eax,%eax - jz 20f /* All good */ - -10: movq %rsp,%rdi /* RDI = pt_regs; RSI is already trapnr */ - call early_fixup_exception + call do_early_exception -20: decl early_recursion_flag(%rip) jmp restore_regs_and_return_to_kernel SYM_CODE_END(early_idt_handler_common) -- 2.7.4