| /* SPDX-License-Identifier: GPL-2.0-only */ |
| |
| #ifndef __ASM_UACCESS_ASM_H__ |
| #define __ASM_UACCESS_ASM_H__ |
| |
| #include <asm/asm-offsets.h> |
| #include <asm/domain.h> |
| #include <asm/memory.h> |
| #include <asm/thread_info.h> |
| |
| .macro csdb |
| #ifdef CONFIG_THUMB2_KERNEL |
| .inst.w 0xf3af8014 |
| #else |
| .inst 0xe320f014 |
| #endif |
| .endm |
| |
| .macro check_uaccess, addr:req, size:req, limit:req, tmp:req, bad:req |
| #ifndef CONFIG_CPU_USE_DOMAINS |
| adds \tmp, \addr, #\size - 1 |
| sbcscc \tmp, \tmp, \limit |
| bcs \bad |
| #ifdef CONFIG_CPU_SPECTRE |
| movcs \addr, #0 |
| csdb |
| #endif |
| #endif |
| .endm |
| |
| .macro uaccess_mask_range_ptr, addr:req, size:req, limit:req, tmp:req |
| #ifdef CONFIG_CPU_SPECTRE |
| sub \tmp, \limit, #1 |
| subs \tmp, \tmp, \addr @ tmp = limit - 1 - addr |
| addhs \tmp, \tmp, #1 @ if (tmp >= 0) { |
| subshs \tmp, \tmp, \size @ tmp = limit - (addr + size) } |
| movlo \addr, #0 @ if (tmp < 0) addr = NULL |
| csdb |
| #endif |
| .endm |
| |
| .macro uaccess_disable, tmp, isb=1 |
| #ifdef CONFIG_CPU_SW_DOMAIN_PAN |
| /* |
| * Whenever we re-enter userspace, the domains should always be |
| * set appropriately. |
| */ |
| mov \tmp, #DACR_UACCESS_DISABLE |
| mcr p15, 0, \tmp, c3, c0, 0 @ Set domain register |
| .if \isb |
| instr_sync |
| .endif |
| #endif |
| .endm |
| |
| .macro uaccess_enable, tmp, isb=1 |
| #ifdef CONFIG_CPU_SW_DOMAIN_PAN |
| /* |
| * Whenever we re-enter userspace, the domains should always be |
| * set appropriately. |
| */ |
| mov \tmp, #DACR_UACCESS_ENABLE |
| mcr p15, 0, \tmp, c3, c0, 0 |
| .if \isb |
| instr_sync |
| .endif |
| #endif |
| .endm |
| |
| #ifdef CONFIG_CPU_SW_DOMAIN_PAN |
| #define DACR(x...) x |
| #else |
| #define DACR(x...) |
| #endif |
| |
| /* |
| * Save the address limit on entry to a privileged exception and |
| * if using PAN, save and disable usermode access. |
| */ |
| .macro uaccess_entry, tsk, tmp0, tmp1, tmp2, disable |
| ldr \tmp1, [\tsk, #TI_ADDR_LIMIT] |
| mov \tmp2, #TASK_SIZE |
| str \tmp2, [\tsk, #TI_ADDR_LIMIT] |
| DACR( mrc p15, 0, \tmp0, c3, c0, 0) |
| DACR( str \tmp0, [sp, #SVC_DACR]) |
| str \tmp1, [sp, #SVC_ADDR_LIMIT] |
| .if \disable |
| uaccess_disable \tmp0 |
| .endif |
| .endm |
| |
| /* Restore the user access state previously saved by uaccess_entry */ |
| .macro uaccess_exit, tsk, tmp0, tmp1 |
| ldr \tmp1, [sp, #SVC_ADDR_LIMIT] |
| DACR( ldr \tmp0, [sp, #SVC_DACR]) |
| str \tmp1, [\tsk, #TI_ADDR_LIMIT] |
| DACR( mcr p15, 0, \tmp0, c3, c0, 0) |
| .endm |
| |
| #undef DACR |
| |
| #endif /* __ASM_UACCESS_ASM_H__ */ |
