From e6ae5981ea4b0f6feb223009a5108582e7644f8f Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Mon, 4 Sep 2017 15:21:52 +0100 Subject: target/arm: Don't store M profile PRIMASK and FAULTMASK in daif We currently store the M profile CPU register state PRIMASK and FAULTMASK in the daif field of the CPU state in its I and F bits. This is a legacy from the original implementation, which tried to share the cpu_exec_interrupt code between A profile and M profile. We've since separated out the two cases because they are significantly different, so now there is no common code between M and A profile which looks at env->daif: all the uses are either in A-only or M-only code paths. Sharing the state fields now is just confusing, and will make things awkward when we implement v8M, where the PRIMASK and FAULTMASK registers are banked between security states. Switch M profile over to using v7m.faultmask and v7m.primask fields for these registers. Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-id: 1501692241-23310-10-git-send-email-peter.maydell@linaro.org --- target/arm/machine.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'target/arm/machine.c') diff --git a/target/arm/machine.c b/target/arm/machine.c index 1f66da4a2c..2fb4b76296 100644 --- a/target/arm/machine.c +++ b/target/arm/machine.c @@ -97,6 +97,17 @@ static bool m_needed(void *opaque) return arm_feature(env, ARM_FEATURE_M); } +static const VMStateDescription vmstate_m_faultmask_primask = { + .name = "cpu/m/faultmask-primask", + .version_id = 1, + .minimum_version_id = 1, + .fields = (VMStateField[]) { + VMSTATE_UINT32(env.v7m.faultmask, ARMCPU), + VMSTATE_UINT32(env.v7m.primask, ARMCPU), + VMSTATE_END_OF_LIST() + } +}; + static const VMStateDescription vmstate_m = { .name = "cpu/m", .version_id = 4, @@ -115,6 +126,10 @@ static const VMStateDescription vmstate_m = { VMSTATE_UINT32(env.v7m.mpu_ctrl, ARMCPU), VMSTATE_INT32(env.v7m.exception, ARMCPU), VMSTATE_END_OF_LIST() + }, + .subsections = (const VMStateDescription*[]) { + &vmstate_m_faultmask_primask, + NULL } }; @@ -201,6 +216,24 @@ static int get_cpsr(QEMUFile *f, void *opaque, size_t size, CPUARMState *env = &cpu->env; uint32_t val = qemu_get_be32(f); + if (arm_feature(env, ARM_FEATURE_M)) { + /* If the I or F bits are set then this is a migration from + * an old QEMU which still stored the M profile FAULTMASK + * and PRIMASK in env->daif. Set v7m.faultmask and v7m.primask + * accordingly, and then clear the bits so they don't confuse + * cpsr_write(). For a new QEMU, the bits here will always be + * clear, and the data is transferred using the + * vmstate_m_faultmask_primask subsection. + */ + if (val & CPSR_F) { + env->v7m.faultmask = 1; + } + if (val & CPSR_I) { + env->v7m.primask = 1; + } + val &= ~(CPSR_F | CPSR_I); + } + env->aarch64 = ((val & PSTATE_nRW) == 0); if (is_a64(env)) { -- cgit 1.4.1 From eeade0017698ada9d3049ec9021d094d96304f58 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Mon, 4 Sep 2017 15:21:52 +0100 Subject: target/arm: Don't use cpsr_write/cpsr_read to transfer M profile XPSR For M profile the XPSR is a similar but not identical format to the A profile CPSR/SPSR. (For instance the Thumb bit is in a different place.) For guest accesses we make the M profile code go through xpsr_read() and xpsr_write() which handle the different layout. However for migration we use cpsr_read() and cpsr_write() to marshal state into and out of the migration data stream. This is pretty confusing and works more by luck than anything else. Make M profile migration use xpsr_read() and xpsr_write() instead. The most complicated part of this is handling the possibility that the migration source is an older QEMU which hands us a CPSR format value; helpfully we can always tell the two apart. Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-id: 1501692241-23310-11-git-send-email-peter.maydell@linaro.org --- target/arm/machine.c | 49 ++++++++++++++++++++++++++++++++++--------------- 1 file changed, 34 insertions(+), 15 deletions(-) (limited to 'target/arm/machine.c') diff --git a/target/arm/machine.c b/target/arm/machine.c index 2fb4b76296..3193b00b04 100644 --- a/target/arm/machine.c +++ b/target/arm/machine.c @@ -217,21 +217,37 @@ static int get_cpsr(QEMUFile *f, void *opaque, size_t size, uint32_t val = qemu_get_be32(f); if (arm_feature(env, ARM_FEATURE_M)) { - /* If the I or F bits are set then this is a migration from - * an old QEMU which still stored the M profile FAULTMASK - * and PRIMASK in env->daif. Set v7m.faultmask and v7m.primask - * accordingly, and then clear the bits so they don't confuse - * cpsr_write(). For a new QEMU, the bits here will always be - * clear, and the data is transferred using the - * vmstate_m_faultmask_primask subsection. - */ - if (val & CPSR_F) { - env->v7m.faultmask = 1; - } - if (val & CPSR_I) { - env->v7m.primask = 1; + if (val & XPSR_EXCP) { + /* This is a CPSR format value from an older QEMU. (We can tell + * because values transferred in XPSR format always have zero + * for the EXCP field, and CPSR format will always have bit 4 + * set in CPSR_M.) Rearrange it into XPSR format. The significant + * differences are that the T bit is not in the same place, the + * primask/faultmask info may be in the CPSR I and F bits, and + * we do not want the mode bits. + */ + uint32_t newval = val; + + newval &= (CPSR_NZCV | CPSR_Q | CPSR_IT | CPSR_GE); + if (val & CPSR_T) { + newval |= XPSR_T; + } + /* If the I or F bits are set then this is a migration from + * an old QEMU which still stored the M profile FAULTMASK + * and PRIMASK in env->daif. For a new QEMU, the data is + * transferred using the vmstate_m_faultmask_primask subsection. + */ + if (val & CPSR_F) { + env->v7m.faultmask = 1; + } + if (val & CPSR_I) { + env->v7m.primask = 1; + } + val = newval; } - val &= ~(CPSR_F | CPSR_I); + /* Ignore the low bits, they are handled by vmstate_m. */ + xpsr_write(env, val, ~XPSR_EXCP); + return 0; } env->aarch64 = ((val & PSTATE_nRW) == 0); @@ -252,7 +268,10 @@ static int put_cpsr(QEMUFile *f, void *opaque, size_t size, CPUARMState *env = &cpu->env; uint32_t val; - if (is_a64(env)) { + if (arm_feature(env, ARM_FEATURE_M)) { + /* The low 9 bits are v7m.exception, which is handled by vmstate_m. */ + val = xpsr_read(env) & ~XPSR_EXCP; + } else if (is_a64(env)) { val = pstate_read(env); } else { val = cpsr_read(env); -- cgit 1.4.1