[PATCH 7/8] arm64: Refactor sysinstr exception handling
From: Suzuki K Poulose
Date: Thu Aug 18 2016 - 09:12:15 EST
Right now we trap some of the user space data cache operations
based on a few Errata (ARM 819472, 826319, 827319 and 824069).
We need to trap userspace access to CTR_EL0, if we detect mismatched
cache line size. Since both these traps share the EC, refactor
the handler a little bit to make it a bit more reader friendly.
Cc: Andre Przywara <andre.przywara@xxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
---
arch/arm64/include/asm/esr.h | 48 +++++++++++++++++++++++++++++
arch/arm64/kernel/traps.c | 73 ++++++++++++++++++++++++++++----------------
2 files changed, 95 insertions(+), 26 deletions(-)
diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
index f772e15..2a8f6c3 100644
--- a/arch/arm64/include/asm/esr.h
+++ b/arch/arm64/include/asm/esr.h
@@ -109,6 +109,54 @@
((ESR_ELx_EC_BRK64 << ESR_ELx_EC_SHIFT) | ESR_ELx_IL | \
((imm) & 0xffff))
+/* ISS field definitions for System instruction traps */
+#define ESR_ELx_SYS64_ISS_RES0_SHIFT 22
+#define ESR_ELx_SYS64_ISS_RES0_MASK (UL(0x7) << ESR_ELx_SYS64_ISS_RES0_SHIFT)
+#define ESR_ELx_SYS64_ISS_DIR_MASK 0x1
+#define ESR_ELx_SYS64_ISS_DIR_READ 0x1
+#define ESR_ELx_SYS64_ISS_DIR_WRITE 0x0
+
+#define ESR_ELx_SYS64_ISS_RT_SHIFT 5
+#define ESR_ELx_SYS64_ISS_RT_MASK (UL(0x1f) << ESR_ELx_SYS64_ISS_RT_SHIFT)
+#define ESR_ELx_SYS64_ISS_CRm_SHIFT 1
+#define ESR_ELx_SYS64_ISS_CRm_MASK (UL(0xf) << ESR_ELx_SYS64_ISS_CRm_SHIFT)
+#define ESR_ELx_SYS64_ISS_CRn_SHIFT 10
+#define ESR_ELx_SYS64_ISS_CRn_MASK (UL(0xf) << ESR_ELx_SYS64_ISS_CRn_SHIFT)
+#define ESR_ELx_SYS64_ISS_Op1_SHIFT 14
+#define ESR_ELx_SYS64_ISS_Op1_MASK (UL(0x7) << ESR_ELx_SYS64_ISS_Op1_SHIFT)
+#define ESR_ELx_SYS64_ISS_Op2_SHIFT 17
+#define ESR_ELx_SYS64_ISS_Op2_MASK (UL(0x7) << ESR_ELx_SYS64_ISS_Op2_SHIFT)
+#define ESR_ELx_SYS64_ISS_Op0_SHIFT 20
+#define ESR_ELx_SYS64_ISS_Op0_MASK (UL(0x3) << ESR_ELx_SYS64_ISS_Op0_SHIFT)
+#define ESR_ELx_SYS64_ISS_SYS_MASK (ESR_ELx_SYS64_ISS_Op0_MASK | \
+ ESR_ELx_SYS64_ISS_Op1_MASK | \
+ ESR_ELx_SYS64_ISS_Op2_MASK | \
+ ESR_ELx_SYS64_ISS_CRn_MASK | \
+ ESR_ELx_SYS64_ISS_CRm_MASK)
+#define ESR_ELx_SYS64_ISS_SYS_VAL(Op0, Op1, Op2, CRn, CRm) \
+ (((Op0) << ESR_ELx_SYS64_ISS_Op0_SHIFT) | \
+ ((Op1) << ESR_ELx_SYS64_ISS_Op1_SHIFT) | \
+ ((Op2) << ESR_ELx_SYS64_ISS_Op2_SHIFT) | \
+ ((CRn) << ESR_ELx_SYS64_ISS_CRn_SHIFT) | \
+ ((CRm) << ESR_ELx_SYS64_ISS_CRm_SHIFT))
+/*
+ * User space cache operations have the following sysreg encoding
+ * in System instructions.
+ * Op0=1, Op1=3, Op2=1, CRn=7, CRm={ 5, 10, 11, 14 }, WRITE (L=0)
+ */
+#define ESR_ELx_SYS64_ISS_CRm_DC_CIVAC 14
+#define ESR_ELx_SYS64_ISS_CRm_DC_CVAU 11
+#define ESR_ELx_SYS64_ISS_CRm_DC_CVAC 10
+#define ESR_ELx_SYS64_ISS_CRm_IC_IVAU 5
+
+#define ESR_ELx_SYS64_ISS_U_CACHE_OP_MASK (ESR_ELx_SYS64_ISS_Op0_MASK | \
+ ESR_ELx_SYS64_ISS_Op1_MASK | \
+ ESR_ELx_SYS64_ISS_Op2_MASK | \
+ ESR_ELx_SYS64_ISS_CRn_MASK | \
+ ESR_ELx_SYS64_ISS_DIR_MASK)
+#define ESR_ELx_SYS64_ISS_U_CACHE_OP_VAL \
+ (ESR_ELx_SYS64_ISS_SYS_VAL(1, 3, 1, 7, 0) | \
+ ESR_ELx_SYS64_ISS_DIR_WRITE)
#ifndef __ASSEMBLY__
#include <asm/types.h>
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index e04f838..93c5287 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -447,36 +447,29 @@ void cpu_enable_cache_maint_trap(void *__unused)
: "=r" (res) \
: "r" (address), "i" (-EFAULT) )
-asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
+static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs)
{
unsigned long address;
- int ret;
+ int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
+ int crm = (esr & ESR_ELx_SYS64_ISS_CRm_MASK) >> ESR_ELx_SYS64_ISS_CRm_SHIFT;
+ int ret = 0;
- /* if this is a write with: Op0=1, Op2=1, Op1=3, CRn=7 */
- if ((esr & 0x01fffc01) == 0x0012dc00) {
- int rt = (esr >> 5) & 0x1f;
- int crm = (esr >> 1) & 0x0f;
+ address = (rt == 31) ? 0 : regs->regs[rt];
- address = (rt == 31) ? 0 : regs->regs[rt];
-
- switch (crm) {
- case 11: /* DC CVAU, gets promoted */
- __user_cache_maint("dc civac", address, ret);
- break;
- case 10: /* DC CVAC, gets promoted */
- __user_cache_maint("dc civac", address, ret);
- break;
- case 14: /* DC CIVAC */
- __user_cache_maint("dc civac", address, ret);
- break;
- case 5: /* IC IVAU */
- __user_cache_maint("ic ivau", address, ret);
- break;
- default:
- force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
- return;
- }
- } else {
+ switch (crm) {
+ case ESR_ELx_SYS64_ISS_CRm_DC_CVAU: /* DC CVAU, gets promoted */
+ __user_cache_maint("dc civac", address, ret);
+ break;
+ case ESR_ELx_SYS64_ISS_CRm_DC_CVAC: /* DC CVAC, gets promoted */
+ __user_cache_maint("dc civac", address, ret);
+ break;
+ case ESR_ELx_SYS64_ISS_CRm_DC_CIVAC: /* DC CIVAC */
+ __user_cache_maint("dc civac", address, ret);
+ break;
+ case ESR_ELx_SYS64_ISS_CRm_IC_IVAU: /* IC IVAU */
+ __user_cache_maint("ic ivau", address, ret);
+ break;
+ default:
force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
return;
}
@@ -487,6 +480,34 @@ asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
regs->pc += 4;
}
+struct sys64_hook {
+ unsigned int esr_mask;
+ unsigned int esr_val;
+ void (*handler)(unsigned int esr, struct pt_regs *regs);
+};
+
+static struct sys64_hook sys64_hooks[] = {
+ {
+ .esr_mask = ESR_ELx_SYS64_ISS_U_CACHE_OP_MASK,
+ .esr_val = ESR_ELx_SYS64_ISS_U_CACHE_OP_VAL,
+ .handler = user_cache_maint_handler,
+ },
+ {},
+};
+
+asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
+{
+ struct sys64_hook *hook;
+
+ for (hook = sys64_hooks; hook->handler; hook++)
+ if ((hook->esr_mask & esr) == hook->esr_val) {
+ hook->handler(esr, regs);
+ return;
+ }
+
+ force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
+}
+
long compat_arm_syscall(struct pt_regs *regs);
asmlinkage long do_ni_syscall(struct pt_regs *regs)
--
2.7.4