Re: [PATCHv3 08/11] arm64: Check for selected granule support
From: Suzuki K. Poulose
Date: Thu Oct 15 2015 - 08:59:08 EST
On 15/10/15 13:37, Mark Rutland wrote:
On Thu, Oct 15, 2015 at 12:25:33PM +0100, Suzuki K. Poulose wrote:
On Thu, Oct 15, 2015 at 11:45:15AM +0100, Mark Rutland wrote:
On Wed, Oct 14, 2015 at 04:13:47PM -0500, Jeremy Linton wrote:
On 10/14/2015 06:20 AM, Suzuki K. Poulose wrote:
----8>----
Author: Suzuki K. Poulose <suzuki.poulose@xxxxxxx>
Date: Wed Oct 14 11:25:16 2015 +0100
arm64: Check for selected granule support
Ensure that the selected page size is supported by the CPU(s). If it isn't
park the CPU. A check is added to the EFI stub to detect if the boot CPU
supports the page size, failing which, we fail the boot gracefully, with
an error message.
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@xxxxxxx>
[ Added a check to EFI stub ]
Signed-off-by: Jeremy Linton <jeremy.linton@xxxxxxx>
Your sign-off should be last, given you are taking resposibility for
Jeremy's patch.
OK, I was a bit confused about how it should look like. I kept it on top
so that I could add [ ] for Jeremy's contribution.
However, I would prefer that the EFI stub addition were a separate/later
patch.
OK, that makes sense.
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index a7f3d4b..72d814c 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
+#define ID_AA64MMFR0_TGRAN4_NI 0xf
+#define ID_AA64MMFR0_TGRAN4_ON 0x0
+#define ID_AA64MMFR0_TGRAN64_NI 0xf
+#define ID_AA64MMFR0_TGRAN64_ON 0x0
+#define ID_AA64MMFR0_TGRAN16_NI 0x0
+#define ID_AA64MMFR0_TGRAN16_ON 0x1
I still don't like "ON" here -- I thought these would also be changed
s/ON/SUPPORTED/.
I know and I expected that. I have "_ON" in my 'CPU feature' series, which
will/can be reused here. Hence kept it _ON. I can change it everywhere to
_SUPPORTED, since I may need to spin another version for that.
#include <linux/efi.h>
#include <asm/efi.h>
+#include <asm/sysreg.h>
#include <asm/sections.h>
Nit: include order.
OK
+#if defined(CONFIG_ARM64_4K_PAGES)
+#define PAGE_SIZE_STR "4K"
+#elif defined(CONFIG_ARM64_64K_PAGES)
+#define PAGE_SIZE_STR "64K"
+#endif
+
efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg,
unsigned long *image_addr,
unsigned long *image_size,
@@ -25,6 +32,17 @@ efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg,
unsigned long kernel_size, kernel_memsize = 0;
unsigned long nr_pages;
void *old_image_addr = (void *)*image_addr;
+ u64 aa64mmfr0_el1;
+
+ /*
+ * Check to see if the CPU supports the requested pagesize
+ */
+ asm volatile("mrs %0, ID_AA64MMFR0_EL1" : "=r" (aa64mmfr0_el1));
Can we not use read_cpuid() or similar here?
Yes, I will try that out. I didn't want to include additional header-files
in efi-stub.c.
+ aa64mmfr0_el1 >>= ID_AA64MMFR0_TGRAN_SHIFT;
... and can we not do the shift and mask in one go?
+ if ((aa64mmfr0_el1 & 0xf) != ID_AA64MMFR0_TGRAN_SUPPORTED) {
+ pr_efi_err(sys_table_arg, PAGE_SIZE_STR" granule not supported by the CPU\n");
Nit: space before the first quote, please.
Will do
Thanks
Suzuki
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