arm64: Refactor sysinstr exception handling

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: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
index f772e15..9875b32 100644 (file)
--- 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 (file)
--- 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)