Alexandre Ghiti 3f105a7427
riscv: Sync efi page table's kernel mappings before switching
The EFI page table is initially created as a copy of the kernel page table.
With VMAP_STACK enabled, kernel stacks are allocated in the vmalloc area:
if the stack is allocated in a new PGD (one that was not present at the
moment of the efi page table creation or not synced in a previous vmalloc
fault), the kernel will take a trap when switching to the efi page table
when the vmalloc kernel stack is accessed, resulting in a kernel panic.

Fix that by updating the efi kernel mappings before switching to the efi
page table.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Fixes: b91540d52a08 ("RISC-V: Add EFI runtime services")
Tested-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20221121133303.1782246-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-11-28 16:36:34 -08:00

48 lines
1.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2020 Western Digital Corporation or its affiliates.
*/
#ifndef _ASM_EFI_H
#define _ASM_EFI_H
#include <asm/csr.h>
#include <asm/io.h>
#include <asm/mmu_context.h>
#include <asm/ptrace.h>
#include <asm/tlbflush.h>
#include <asm/pgalloc.h>
#ifdef CONFIG_EFI
extern void efi_init(void);
#else
#define efi_init()
#endif
int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md);
int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
#define arch_efi_call_virt_setup() ({ \
sync_kernel_mappings(efi_mm.pgd); \
efi_virtmap_load(); \
})
#define arch_efi_call_virt_teardown() efi_virtmap_unload()
#define ARCH_EFI_IRQ_FLAGS_MASK (SR_IE | SR_SPIE)
/* Load initrd anywhere in system RAM */
static inline unsigned long efi_get_max_initrd_addr(unsigned long image_addr)
{
return ULONG_MAX;
}
#define alloc_screen_info(x...) (&screen_info)
static inline void free_screen_info(struct screen_info *si)
{
}
void efi_virtmap_load(void);
void efi_virtmap_unload(void);
#endif /* _ASM_EFI_H */