arm64: Check for selected granule support

Ensure that the selected page size is supported by the CPU(s). If it doesn't
park it.

Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index a7f3d4b2514d615e191c86feb3da5da9351f173f..d59cb231a6735e09bb32df473b820b9887ab6430 100644 (file)
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -44,6 +44,26 @@
 #define SET_PSTATE_PAN(x) __inst_arm(0xd5000000 | REG_PSTATE_PAN_IMM |\
                                     (!!x)<<8 | 0x1f)
 
+
+#define ID_AA64MMFR0_TGRAN4_SHIFT      28
+#define ID_AA64MMFR0_TGRAN64_SHIFT     24
+#define ID_AA64MMFR0_TGRAN16_SHIFT     20
+
+#define ID_AA64MMFR0_TGRAN4_NI         0xf
+#define ID_AA64MMFR0_TGRAN4_SUPPORTED  0x0
+#define ID_AA64MMFR0_TGRAN64_NI                0xf
+#define ID_AA64MMFR0_TGRAN64_SUPPORTED 0x0
+#define ID_AA64MMFR0_TGRAN16_NI                0x0
+#define ID_AA64MMFR0_TGRAN16_SUPPORTED 0x1
+
+#if defined(CONFIG_ARM64_4K_PAGES)
+#define ID_AA64MMFR0_TGRAN_SHIFT       ID_AA64MMFR0_TGRAN4_SHIFT
+#define ID_AA64MMFR0_TGRAN_SUPPORTED   ID_AA64MMFR0_TGRAN4_SUPPORTED
+#elif defined(CONFIG_ARM64_64K_PAGES)
+#define ID_AA64MMFR0_TGRAN_SHIFT       ID_AA64MMFR0_TGRAN64_SHIFT
+#define ID_AA64MMFR0_TGRAN_SUPPORTED   ID_AA64MMFR0_TGRAN64_SUPPORTED
+#endif
+
 #ifdef __ASSEMBLY__
 
        .irp    num,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 7ace955b0f31e476c557812ba3b1a07e42777153..514c1cc9fdc5bc5da0a3b5a1cf30ae8523bb3f24 100644 (file)
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -31,10 +31,11 @@
 #include <asm/cputype.h>
 #include <asm/kernel-pgtable.h>
 #include <asm/memory.h>
-#include <asm/thread_info.h>
 #include <asm/pgtable-hwdef.h>
 #include <asm/pgtable.h>
 #include <asm/page.h>
+#include <asm/sysreg.h>
+#include <asm/thread_info.h>
 #include <asm/virt.h>
 
 #define __PHYS_OFFSET  (KERNEL_START - TEXT_OFFSET)
@@ -613,10 +614,17 @@ ENDPROC(__secondary_switched)
  *  x0  = SCTLR_EL1 value for turning on the MMU.
  *  x27 = *virtual* address to jump to upon completion
  *
- * other registers depend on the function called upon completion
+ * Other registers depend on the function called upon completion.
+ *
+ * Checks if the selected granule size is supported by the CPU.
+ * If it isn't, park the CPU
  */
        .section        ".idmap.text", "ax"
 __enable_mmu:
+       mrs     x1, ID_AA64MMFR0_EL1
+       ubfx    x2, x1, #ID_AA64MMFR0_TGRAN_SHIFT, 4
+       cmp     x2, #ID_AA64MMFR0_TGRAN_SUPPORTED
+       b.ne    __no_granule_support
        ldr     x5, =vectors
        msr     vbar_el1, x5
        msr     ttbr0_el1, x25                  // load TTBR0
@@ -634,3 +642,8 @@ __enable_mmu:
        isb
        br      x27
 ENDPROC(__enable_mmu)
+
+__no_granule_support:
+       wfe
+       b __no_granule_support
+ENDPROC(__no_granule_support)