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x86: add inline function to fetch cr2

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Better to encapsulate asm operations in inline functions than
embed directly in other C code.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2020-11-16 09:22:18 -08:00 committed by Anas Nashif
parent 3f7ae0d749
commit 5b5bdb5fbd
2 changed files with 20 additions and 6 deletions
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11
arch/x86/core/fatal.c
View file

@ -298,13 +298,12 @@ static void log_exception(uintptr_t vector, uintptr_t code)
static void dump_page_fault(z_arch_esf_t *esf)
{
uintptr_t err, cr2;
/* See Section 6.15 of the IA32 Software Developer's Manual vol 3 */
__asm__ ("mov %%cr2, %0" : "=r" (cr2));
uintptr_t err;
void *cr2;
cr2 = z_x86_cr2_get();
err = esf_get_code(esf);
LOG_ERR("Page fault at address 0x%lx (error code 0x%lx)", cr2, err);
LOG_ERR("Page fault at address %p (error code 0x%lx)", cr2, err);
if ((err & RSVD) != 0) {
LOG_ERR("Reserved bits set in page tables");
@ -325,7 +324,7 @@ static void dump_page_fault(z_arch_esf_t *esf)
}
#ifdef CONFIG_X86_MMU
z_x86_dump_mmu_flags(get_ptables(esf), (void *)cr2);
z_x86_dump_mmu_flags(get_ptables(esf), cr2);
#endif /* CONFIG_X86_MMU */
}
#endif /* CONFIG_EXCEPTION_DEBUG */

15
arch/x86/include/x86_mmu.h
View file

@ -166,6 +166,21 @@ static inline pentry_t *z_x86_page_tables_get(void)
return (pentry_t *)z_x86_cr3_get();
}
/* Return cr2 value, which contains the page fault linear address.
* See Section 6.15 of the IA32 Software Developer's Manual vol 3.
* Used by page fault handling code.
*/
static inline void *z_x86_cr2_get(void)
{
void *cr2;
#ifdef CONFIG_X86_64
__asm__ volatile("movq %%cr2, %0\n\t" : "=r" (cr2));
#else
__asm__ volatile("movl %%cr2, %0\n\t" : "=r" (cr2));
#endif
return cr2;
}
/* Kernel's page table. This is in CR3 for all supervisor threads.
* if KPTI is enabled, we switch to this when handling exceptions or syscalls
*/