diff options
| -rw-r--r-- | arch/arm/include/asm/mpu.h | 1 | ||||
| -rw-r--r-- | arch/arm/kernel/head-nommu.S | 16 | ||||
| -rw-r--r-- | arch/arm/kernel/signal.c | 9 |
3 files changed, 24 insertions, 2 deletions
diff --git a/arch/arm/include/asm/mpu.h b/arch/arm/include/asm/mpu.h index 001483465aa4..c3247cc2fe08 100644 --- a/arch/arm/include/asm/mpu.h +++ b/arch/arm/include/asm/mpu.h @@ -46,6 +46,7 @@ #define MPU_PROBE_REGION 0 #define MPU_BG_REGION 1 #define MPU_RAM_REGION 2 +#define MPU_VECTORS_REGION 3 /* Maximum number of regions Linux is interested in */ #define MPU_MAX_REGIONS 16 diff --git a/arch/arm/kernel/head-nommu.S b/arch/arm/kernel/head-nommu.S index 13741d004de5..75f14cc3e073 100644 --- a/arch/arm/kernel/head-nommu.S +++ b/arch/arm/kernel/head-nommu.S @@ -22,6 +22,7 @@ #include <asm/thread_info.h> #include <asm/v7m.h> #include <asm/mpu.h> +#include <asm/page.h> /* * Kernel startup entry point. @@ -188,6 +189,7 @@ ENDPROC(__after_proc_init) * Region 0: Use this for probing the MPU details, so leave disabled. * Region 1: Background region - covers the whole of RAM as strongly ordered * Region 2: Normal, Shared, cacheable for RAM. From PHYS_OFFSET, size from r6 + * Region 3: Normal, shared, inaccessible from PL0 to protect the vectors page * * r6: Value to be written to DRSR (and IRSR if required) for MPU_RAM_REGION */ @@ -232,6 +234,20 @@ ENTRY(__setup_mpu) setup_region r0, r5, r6, MPU_INSTR_SIDE @ 0x0, BG region, enabled 2: isb + /* Vectors region */ + set_region_nr r0, #MPU_VECTORS_REGION + isb + /* Shared, inaccessible to PL0, rw PL1 */ + mov r0, #CONFIG_VECTORS_BASE @ Cover from VECTORS_BASE + ldr r5,=(MPU_AP_PL1RW_PL0NA | MPU_RGN_NORMAL) + /* Writing N to bits 5:1 (RSR_SZ) --> region size 2^N+1 */ + mov r6, #(((PAGE_SHIFT - 1) << MPU_RSR_SZ) | 1 << MPU_RSR_EN) + + setup_region r0, r5, r6, MPU_DATA_SIDE @ VECTORS_BASE, PL0 NA, enabled + beq 3f @ Memory-map not unified + setup_region r0, r5, r6, MPU_INSTR_SIDE @ VECTORS_BASE, PL0 NA, enabled +3: isb + /* Enable the MPU */ mrc p15, 0, r0, c1, c0, 0 @ Read SCTLR bic r0, r0, #CR_BR @ Disable the 'default mem-map' diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index 296786bdbb73..1c16c35c271a 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -392,14 +392,19 @@ setup_return(struct pt_regs *regs, struct ksignal *ksig, if (ksig->ka.sa.sa_flags & SA_SIGINFO) idx += 3; + /* + * Put the sigreturn code on the stack no matter which return + * mechanism we use in order to remain ABI compliant + */ if (__put_user(sigreturn_codes[idx], rc) || __put_user(sigreturn_codes[idx+1], rc+1)) return 1; - if (cpsr & MODE32_BIT) { + if ((cpsr & MODE32_BIT) && !IS_ENABLED(CONFIG_ARM_MPU)) { /* * 32-bit code can use the new high-page - * signal return code support. + * signal return code support except when the MPU has + * protected the vectors page from PL0 */ retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb; } else { |