diff options
| author | Peter Maydell <peter.maydell@linaro.org> | 2014-08-19 18:56:26 +0100 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2014-08-19 19:02:03 +0100 |
| commit | 4051e12c5df1c46b542b28ed43f1614a42245ecf (patch) | |
| tree | 06aee211a240ff8caa2712de853f62e6c1462c1e /target-arm/cpu.h | |
| parent | 48eb3ae64b3e17151cf8f42af185e6f43baf707b (diff) | |
target-arm: Don't allow AArch32 to access RES0 CPSR bits
The CPSR has a new-in-v8 execution state bit (IL), and
also some state which has effects in AArch32 but appears
only in the SPSR format (SS) but is RES0 in the CPSR.
Add the IL bit to CPSR_EXEC, and enforce that guest direct
reads and writes to CPSR can't read or write the RES0
bits, so the guest can't get at the SS bit which we store
in uncached_cpsr. This includes not permitting exception
returns to copy reserved bits from an SPSR into CPSR.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Diffstat (limited to 'target-arm/cpu.h')
| -rw-r--r-- | target-arm/cpu.h | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/target-arm/cpu.h b/target-arm/cpu.h index 79205ba335..8380c136e2 100644 --- a/target-arm/cpu.h +++ b/target-arm/cpu.h @@ -411,7 +411,13 @@ int arm_cpu_handle_mmu_fault(CPUState *cpu, vaddr address, int rw, #define CPSR_E (1U << 9) #define CPSR_IT_2_7 (0xfc00U) #define CPSR_GE (0xfU << 16) -#define CPSR_RESERVED (0xfU << 20) +#define CPSR_IL (1U << 20) +/* Note that the RESERVED bits include bit 21, which is PSTATE_SS in + * an AArch64 SPSR but RES0 in AArch32 SPSR and CPSR. In QEMU we use + * env->uncached_cpsr bit 21 to store PSTATE.SS when executing in AArch32, + * where it is live state but not accessible to the AArch32 code. + */ +#define CPSR_RESERVED (0x7U << 21) #define CPSR_J (1U << 24) #define CPSR_IT_0_1 (3U << 25) #define CPSR_Q (1U << 27) @@ -428,7 +434,9 @@ int arm_cpu_handle_mmu_fault(CPUState *cpu, vaddr address, int rw, /* Bits writable in user mode. */ #define CPSR_USER (CPSR_NZCV | CPSR_Q | CPSR_GE) /* Execution state bits. MRS read as zero, MSR writes ignored. */ -#define CPSR_EXEC (CPSR_T | CPSR_IT | CPSR_J) +#define CPSR_EXEC (CPSR_T | CPSR_IT | CPSR_J | CPSR_IL) +/* Mask of bits which may be set by exception return copying them from SPSR */ +#define CPSR_ERET_MASK (~CPSR_RESERVED) #define TTBCR_N (7U << 0) /* TTBCR.EAE==0 */ #define TTBCR_T0SZ (7U << 0) /* TTBCR.EAE==1 */ |