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target/arm: ensure we use current exception state after SCR update

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A write to the SCR can change the effective EL by droppping the system
from secure to non-secure mode. However if we use a cached current_el
from before the change we'll rebuild the flags incorrectly. To fix
this we introduce the ARM_CP_NEWEL CP flag to indicate the new EL
should be used when recomputing the flags.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20191212114734.6962-1-alex.bennee@linaro.org
Cc: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20191209143723.6368-1-alex.bennee@linaro.org>
Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Alex Bennée 2019-12-12 11:47:34 +00:00 committed by Peter Maydell
parent b8b69f4c45
commit f80741d107
4 changed files with 25 additions and 4 deletions
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8
target/arm/cpu.h
View file

@ -2238,6 +2238,9 @@ static inline uint64_t cpreg_to_kvm_id(uint32_t cpregid)
* RAISES_EXC is for when the read or write hook might raise an exception;
* the generated code will synchronize the CPU state before calling the hook
* so that it is safe for the hook to call raise_exception().
* NEWEL is for writes to registers that might change the exception
* level - typically on older ARM chips. For those cases we need to
* re-read the new el when recomputing the translation flags.
*/
#define ARM_CP_SPECIAL 0x0001
#define ARM_CP_CONST 0x0002
@ -2257,10 +2260,11 @@ static inline uint64_t cpreg_to_kvm_id(uint32_t cpregid)
#define ARM_CP_SVE 0x2000
#define ARM_CP_NO_GDB 0x4000
#define ARM_CP_RAISES_EXC 0x8000
#define ARM_CP_NEWEL 0x10000
/* Used only as a terminator for ARMCPRegInfo lists */
#define ARM_CP_SENTINEL 0xffff
#define ARM_CP_SENTINEL 0xfffff
/* Mask of only the flag bits in a type field */
#define ARM_CP_FLAG_MASK 0xf0ff
#define ARM_CP_FLAG_MASK 0x1f0ff
/* Valid values for ARMCPRegInfo state field, indicating which of
* the AArch32 and AArch64 execution states this register is visible in.

14
target/arm/helper.c
View file

@ -5133,7 +5133,7 @@ static const ARMCPRegInfo el3_cp_reginfo[] = {
.opc0 = 3, .opc1 = 6, .crn = 1, .crm = 1, .opc2 = 0,
.access = PL3_RW, .fieldoffset = offsetof(CPUARMState, cp15.scr_el3),
.resetvalue = 0, .writefn = scr_write },
{ .name = "SCR", .type = ARM_CP_ALIAS,
{ .name = "SCR", .type = ARM_CP_ALIAS | ARM_CP_NEWEL,
.cp = 15, .opc1 = 0, .crn = 1, .crm = 1, .opc2 = 0,
.access = PL1_RW, .accessfn = access_trap_aa32s_el1,
.fieldoffset = offsetoflow32(CPUARMState, cp15.scr_el3),
@ -11472,6 +11472,18 @@ void HELPER(rebuild_hflags_m32)(CPUARMState *env, int el)
env->hflags = rebuild_hflags_m32(env, fp_el, mmu_idx);
}
/*
* If we have triggered a EL state change we can't rely on the
* translator having passed it too us, we need to recompute.
*/
void HELPER(rebuild_hflags_a32_newel)(CPUARMState *env)
{
int el = arm_current_el(env);
int fp_el = fp_exception_el(env, el);
ARMMMUIdx mmu_idx = arm_mmu_idx_el(env, el);
env->hflags = rebuild_hflags_a32(env, fp_el, mmu_idx);
}
void HELPER(rebuild_hflags_a32)(CPUARMState *env, int el)
{
int fp_el = fp_exception_el(env, el);

1
target/arm/helper.h
View file

@ -91,6 +91,7 @@ DEF_HELPER_2(get_user_reg, i32, env, i32)
DEF_HELPER_3(set_user_reg, void, env, i32, i32)
DEF_HELPER_FLAGS_2(rebuild_hflags_m32, TCG_CALL_NO_RWG, void, env, int)
DEF_HELPER_FLAGS_1(rebuild_hflags_a32_newel, TCG_CALL_NO_RWG, void, env)
DEF_HELPER_FLAGS_2(rebuild_hflags_a32, TCG_CALL_NO_RWG, void, env, int)
DEF_HELPER_FLAGS_2(rebuild_hflags_a64, TCG_CALL_NO_RWG, void, env, int)

6
target/arm/translate.c
View file

@ -7083,7 +7083,11 @@ static int disas_coproc_insn(DisasContext *s, uint32_t insn)
if (arm_dc_feature(s, ARM_FEATURE_M)) {
gen_helper_rebuild_hflags_m32(cpu_env, tcg_el);
} else {
gen_helper_rebuild_hflags_a32(cpu_env, tcg_el);
if (ri->type & ARM_CP_NEWEL) {
gen_helper_rebuild_hflags_a32_newel(cpu_env);
} else {
gen_helper_rebuild_hflags_a32(cpu_env, tcg_el);
}
}
tcg_temp_free_i32(tcg_el);
/*