[PATCH v3 8/9] arm64: Refactor sysinstr exception handling
From: Suzuki K Poulose
Date: Mon Sep 05 2016 - 06:00:32 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 | 76 ++++++++++++++++++++++++++++++++++++++------
arch/arm64/kernel/traps.c | 73 +++++++++++++++++++++++++++---------------
2 files changed, 114 insertions(+), 35 deletions(-)
diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
index f772e15..9875b32 100644
--- a/arch/arm64/include/asm/esr.h
+++ b/arch/arm64/include/asm/esr.h
@@ -78,6 +78,23 @@
#define ESR_ELx_IL (UL(1) << 25)
#define ESR_ELx_ISS_MASK (ESR_ELx_IL - 1)
+
+/* ISS field definitions shared by different classes */
+#define ESR_ELx_WNR (UL(1) << 6)
+
+/* Shared ISS field definitions for Data/Instruction aborts */
+#define ESR_ELx_EA (UL(1) << 9)
+#define ESR_ELx_S1PTW (UL(1) << 7)
+
+/* Shared ISS fault status code(IFSC/DFSC) for Data/Instruction aborts */
+#define ESR_ELx_FSC (0x3F)
+#define ESR_ELx_FSC_TYPE (0x3C)
+#define ESR_ELx_FSC_EXTABT (0x10)
+#define ESR_ELx_FSC_ACCESS (0x08)
+#define ESR_ELx_FSC_FAULT (0x04)
+#define ESR_ELx_FSC_PERM (0x0C)
+
+/* ISS field definitions for Data Aborts */
#define ESR_ELx_ISV (UL(1) << 24)
#define ESR_ELx_SAS_SHIFT (22)
#define ESR_ELx_SAS (UL(3) << ESR_ELx_SAS_SHIFT)
@@ -86,16 +103,9 @@
#define ESR_ELx_SRT_MASK (UL(0x1F) << ESR_ELx_SRT_SHIFT)
#define ESR_ELx_SF (UL(1) << 15)
#define ESR_ELx_AR (UL(1) << 14)
-#define ESR_ELx_EA (UL(1) << 9)
#define ESR_ELx_CM (UL(1) << 8)
-#define ESR_ELx_S1PTW (UL(1) << 7)
-#define ESR_ELx_WNR (UL(1) << 6)
-#define ESR_ELx_FSC (0x3F)
-#define ESR_ELx_FSC_TYPE (0x3C)
-#define ESR_ELx_FSC_EXTABT (0x10)
-#define ESR_ELx_FSC_ACCESS (0x08)
-#define ESR_ELx_FSC_FAULT (0x04)
-#define ESR_ELx_FSC_PERM (0x0C)
+
+/* ISS field definitions for exceptions taken in to Hyp */
#define ESR_ELx_CV (UL(1) << 24)
#define ESR_ELx_COND_SHIFT (20)
#define ESR_ELx_COND_MASK (UL(0xF) << ESR_ELx_COND_SHIFT)
@@ -109,6 +119,54 @@
((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_EL0_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_EL0_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..224f64e 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_EL0_CACHE_OP_MASK,
+ .esr_val = ESR_ELx_SYS64_ISS_EL0_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