diff options
Diffstat (limited to 'arch/arm/include/asm/uaccess-asm.h')
| -rw-r--r-- | arch/arm/include/asm/uaccess-asm.h | 44 |
1 files changed, 43 insertions, 1 deletions
diff --git a/arch/arm/include/asm/uaccess-asm.h b/arch/arm/include/asm/uaccess-asm.h index ea42ba25920f..4bccd895d954 100644 --- a/arch/arm/include/asm/uaccess-asm.h +++ b/arch/arm/include/asm/uaccess-asm.h @@ -39,7 +39,7 @@ #endif .endm -#ifdef CONFIG_CPU_SW_DOMAIN_PAN +#if defined(CONFIG_CPU_SW_DOMAIN_PAN) .macro uaccess_disable, tmp, isb=1 /* @@ -65,6 +65,37 @@ .endif .endm +#elif defined(CONFIG_CPU_TTBR0_PAN) + + .macro uaccess_disable, tmp, isb=1 + /* + * Disable TTBR0 page table walks (EDP0 = 1), use the reserved ASID + * from TTBR1 (A1 = 1) and enable TTBR1 page table walks for kernel + * addresses by reducing TTBR0 range to 32MB (T0SZ = 7). + */ + mrc p15, 0, \tmp, c2, c0, 2 @ read TTBCR + orr \tmp, \tmp, #TTBCR_EPD0 | TTBCR_T0SZ_MASK + orr \tmp, \tmp, #TTBCR_A1 + mcr p15, 0, \tmp, c2, c0, 2 @ write TTBCR + .if \isb + instr_sync + .endif + .endm + + .macro uaccess_enable, tmp, isb=1 + /* + * Enable TTBR0 page table walks (T0SZ = 0, EDP0 = 0) and ASID from + * TTBR0 (A1 = 0). + */ + mrc p15, 0, \tmp, c2, c0, 2 @ read TTBCR + bic \tmp, \tmp, #TTBCR_EPD0 | TTBCR_T0SZ_MASK + bic \tmp, \tmp, #TTBCR_A1 + mcr p15, 0, \tmp, c2, c0, 2 @ write TTBCR + .if \isb + instr_sync + .endif + .endm + #else .macro uaccess_disable, tmp, isb=1 @@ -81,6 +112,12 @@ #define DACR(x...) #endif +#ifdef CONFIG_CPU_TTBR0_PAN +#define PAN(x...) x +#else +#define PAN(x...) +#endif + /* * Save the address limit on entry to a privileged exception. * @@ -94,6 +131,8 @@ .macro uaccess_entry, tsk, tmp0, tmp1, tmp2, disable DACR( mrc p15, 0, \tmp0, c3, c0, 0) DACR( str \tmp0, [sp, #SVC_DACR]) + PAN( mrc p15, 0, \tmp0, c2, c0, 2) + PAN( str \tmp0, [sp, #SVC_TTBCR]) .if \disable && IS_ENABLED(CONFIG_CPU_SW_DOMAIN_PAN) /* kernel=client, user=no access */ mov \tmp2, #DACR_UACCESS_DISABLE @@ -112,8 +151,11 @@ .macro uaccess_exit, tsk, tmp0, tmp1 DACR( ldr \tmp0, [sp, #SVC_DACR]) DACR( mcr p15, 0, \tmp0, c3, c0, 0) + PAN( ldr \tmp0, [sp, #SVC_TTBCR]) + PAN( mcr p15, 0, \tmp0, c2, c0, 2) .endm #undef DACR +#undef PAN #endif /* __ASM_UACCESS_ASM_H__ */ |