diff options
| author | Peter Maydell <peter.maydell@linaro.org> | 2016-10-24 16:26:50 +0100 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2016-10-24 16:26:50 +0100 |
| commit | e97da98f1173c764e8fd8d2c84f84ec3bdc87488 (patch) | |
| tree | 2c4c6f982b4353e5c223b7d642c52f9258378359 | |
| parent | 59811a320d6b2a6db2646f908bb016dd8553df27 (diff) | |
target-arm: Make page size a runtime setting
Rather than defining TARGET_PAGE_BITS to always be 10,
switch to using a value picked at runtime. This allows us
to use 4K pages for modern ARM CPUs (and in particular all
64-bit CPUs) without having to drop support for the old
ARMv5 CPUs which had 1K pages.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
| -rw-r--r-- | target-arm/cpu.c | 24 | ||||
| -rw-r--r-- | target-arm/cpu.h | 9 |
2 files changed, 29 insertions, 4 deletions
diff --git a/target-arm/cpu.c b/target-arm/cpu.c index 1b9540e085..c94a324540 100644 --- a/target-arm/cpu.c +++ b/target-arm/cpu.c @@ -576,6 +576,7 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp) ARMCPU *cpu = ARM_CPU(dev); ARMCPUClass *acc = ARM_CPU_GET_CLASS(dev); CPUARMState *env = &cpu->env; + int pagebits; /* Some features automatically imply others: */ if (arm_feature(env, ARM_FEATURE_V8)) { @@ -631,6 +632,29 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp) set_feature(env, ARM_FEATURE_THUMB_DSP); } + if (arm_feature(env, ARM_FEATURE_V7) && + !arm_feature(env, ARM_FEATURE_M) && + !arm_feature(env, ARM_FEATURE_MPU)) { + /* v7VMSA drops support for the old ARMv5 tiny pages, so we + * can use 4K pages. + */ + pagebits = 12; + } else { + /* For CPUs which might have tiny 1K pages, or which have an + * MPU and might have small region sizes, stick with 1K pages. + */ + pagebits = 10; + } + if (!set_preferred_target_page_bits(pagebits)) { + /* This can only ever happen for hotplugging a CPU, or if + * the board code incorrectly creates a CPU which it has + * promised via minimum_page_size that it will not. + */ + error_setg(errp, "This CPU requires a smaller page size than the " + "system is using"); + return; + } + if (cpu->reset_hivecs) { cpu->reset_sctlr |= (1 << 13); } diff --git a/target-arm/cpu.h b/target-arm/cpu.h index 2218c00dad..6695390075 100644 --- a/target-arm/cpu.h +++ b/target-arm/cpu.h @@ -1766,10 +1766,11 @@ bool write_cpustate_to_list(ARMCPU *cpu); #if defined(CONFIG_USER_ONLY) #define TARGET_PAGE_BITS 12 #else -/* The ARM MMU allows 1k pages. */ -/* ??? Linux doesn't actually use these, and they're deprecated in recent - architecture revisions. Maybe a configure option to disable them. */ -#define TARGET_PAGE_BITS 10 +/* ARMv7 and later CPUs have 4K pages minimum, but ARMv5 and v6 + * have to support 1K tiny pages. + */ +#define TARGET_PAGE_BITS_VARY +#define TARGET_PAGE_BITS_MIN 10 #endif #if defined(TARGET_AARCH64) |