Commit 4b47cdbd authored by Joerg Roedel's avatar Joerg Roedel Committed by Borislav Petkov
Browse files

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: default avatarJoerg Roedel <jroedel@suse.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-36-joro@8bytes.org
parent 097ee5b7

arch/x86/include/asm/pgtable.h

+1 −1
Original line number Diff line number Diff line
@@ -28,7 +28,7 @@ 
#include <asm-generic/pgtable_uffd.h>



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,

arch/x86/include/asm/setup.h

+3 −1
Original line number Diff line number Diff line
@@ -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);

arch/x86/kernel/head64.c

+15 −4
Original line number Diff line number Diff line
@@ -38,6 +38,8 @@ 
#include <asm/fixmap.h>

#include <asm/realmode.h>

#include <asm/desc.h>

#include <asm/extable.h>

#include <asm/trapnr.h>



/*

 * 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)

arch/x86/kernel/head_64.S

+1 −10
Original line number Diff line number Diff line
@@ -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)

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