On Mon, Nov 02, 2020 at 11:34:44AM +0000, Nikos Nikoleris wrote:
> Now that we can change the translation granule at will, and since
> arm64 implementations can support a subset of the architecturally
> defined granules, we need to check and warn the user if the configured
> granule is not supported.
nit: it'd be better for this patch to come before the last patch.
>
> Signed-off-by: Nikos Nikoleris <nikos.nikoleris@xxxxxxx>
> ---
> lib/arm64/asm/processor.h | 65 +++++++++++++++++++++++++++++++++++++++
> lib/arm/mmu.c | 3 ++
> 2 files changed, 68 insertions(+)
>
> diff --git a/lib/arm64/asm/processor.h b/lib/arm64/asm/processor.h
> index 02665b8..0eac928 100644
> --- a/lib/arm64/asm/processor.h
> +++ b/lib/arm64/asm/processor.h
> @@ -117,5 +117,70 @@ static inline u64 get_ctr(void)
>
> extern u32 dcache_line_size;
>
> +static inline unsigned long get_id_aa64mmfr0_el1(void)
> +{
> + unsigned long mmfr0;
> + asm volatile("mrs %0, id_aa64mmfr0_el1" : "=r" (mmfr0));
> + return mmfr0;
> +}
> +
> +/* From arch/arm64/include/asm/cpufeature.h */
> +static inline unsigned int
> +cpuid_feature_extract_unsigned_field_width(u64 features, int field, int width)
> +{
> + return (u64)(features << (64 - width - field)) >> (64 - width);
> +}
> +
> +#define ID_AA64MMFR0_TGRAN4_SHIFT 28
> +#define ID_AA64MMFR0_TGRAN64_SHIFT 24
> +#define ID_AA64MMFR0_TGRAN16_SHIFT 20
> +#define ID_AA64MMFR0_TGRAN4_SUPPORTED 0x0
> +#define ID_AA64MMFR0_TGRAN64_SUPPORTED 0x0
> +#define ID_AA64MMFR0_TGRAN16_SUPPORTED 0x1
> +
> +static inline bool system_supports_64kb_granule(void)
> +{
> + u64 mmfr0;
> + u32 val;
> +
> + mmfr0 = get_id_aa64mmfr0_el1();
> + val = cpuid_feature_extract_unsigned_field_width(
> + mmfr0, ID_AA64MMFR0_TGRAN4_SHIFT,4);
> +
> + return val == ID_AA64MMFR0_TGRAN64_SUPPORTED;
> +}
> +
> +static inline bool system_supports_16kb_granule(void)
> +{
> + u64 mmfr0;
> + u32 val;
> +
> + mmfr0 = get_id_aa64mmfr0_el1();
> + val = cpuid_feature_extract_unsigned_field_width(
> + mmfr0, ID_AA64MMFR0_TGRAN16_SHIFT, 4);
> +
> + return val == ID_AA64MMFR0_TGRAN16_SUPPORTED;
> +}
> +
> +static inline bool system_supports_4kb_granule(void)
> +{
> + u64 mmfr0;
> + u32 val;
> +
> + mmfr0 = get_id_aa64mmfr0_el1();
> + val = cpuid_feature_extract_unsigned_field_width(
> + mmfr0, ID_AA64MMFR0_TGRAN4_SHIFT, 4);
> +
> + return val == ID_AA64MMFR0_TGRAN4_SUPPORTED;
> +}
> +
> +#if PAGE_SIZE == 65536
> +#define system_supports_configured_granule system_supports_64kb_granule
> +#elif PAGE_SIZE == 16384
> +#define system_supports_configured_granule system_supports_16kb_granule
> +#elif PAGE_SIZE == 4096
> +#define system_supports_configured_granule system_supports_4kb_granule
> +#endif
> +
> #endif /* !__ASSEMBLY__ */
> #endif /* _ASMARM64_PROCESSOR_H_ */
> diff --git a/lib/arm/mmu.c b/lib/arm/mmu.c
> index 6d1c75b..51fa745 100644
> --- a/lib/arm/mmu.c
> +++ b/lib/arm/mmu.c
> @@ -163,6 +163,9 @@ void *setup_mmu(phys_addr_t phys_end)
>
> #ifdef __aarch64__
> init_alloc_vpage((void*)(4ul << 30));
> +
> + assert_msg(system_supports_configured_granule(),
> + "Unsupported translation granule %d\n", PAGE_SIZE);
^
needs '%ld' to compile
> #endif
>
> mmu_idmap = alloc_page();
> --
> 2.17.1
>
I don't think we need the three separate functions. How about just
doing the following diff?
Thanks,
drew
diff --git a/lib/arm/mmu.c b/lib/arm/mmu.c
index 540a1e842d5b..fef62f5a9866 100644
--- a/lib/arm/mmu.c
+++ b/lib/arm/mmu.c
@@ -160,6 +160,9 @@ void *setup_mmu(phys_addr_t phys_end)
#ifdef __aarch64__
init_alloc_vpage((void*)(4ul << 30));
+
+ assert_msg(system_supports_granule(PAGE_SIZE),
+ "Unsupported translation granule: %ld\n", PAGE_SIZE);
#endif
mmu_idmap = alloc_page();
diff --git a/lib/arm64/asm/processor.h b/lib/arm64/asm/processor.h
index 02665b84cc7e..dc493d1686bc 100644
--- a/lib/arm64/asm/processor.h
+++ b/lib/arm64/asm/processor.h
@@ -117,5 +117,21 @@ static inline u64 get_ctr(void)
extern u32 dcache_line_size;
+static inline unsigned long get_id_aa64mmfr0_el1(void)
+{
+ unsigned long mmfr0;
+ asm volatile("mrs %0, id_aa64mmfr0_el1" : "=r" (mmfr0));
+ return mmfr0;
+}
+
+static inline bool system_supports_granule(size_t granule)
+{
+ u64 mmfr0 = get_id_aa64mmfr0_el1();
+
+ return ((granule == SZ_4K && ((mmfr0 >> 28) & 0xf) == 0) ||
+ (granule == SZ_64K && ((mmfr0 >> 24) & 0xf) == 0) ||
+ (granule == SZ_16K && ((mmfr0 >> 20) & 0xf) == 1));
+}
+
#endif /* !__ASSEMBLY__ */
#endif /* _ASMARM64_PROCESSOR_H_ */
