[PATCH v8 28/43] arm64: Add ESR decoding for exceptions involving translation level -1

[Ard Biesheuvel <ardb+git@google.com>]

From: Ard Biesheuvel <ardb@kernel.org>

The LPA2 feature introduces new FSC values to report abort exceptions
related to translation level -1. Define these and wire them up.

Reuse the new ESR FSC classification helpers that arrived via the KVM
arm64 tree, and update the one for translation faults to check
specifically for a translation fault at level -1. (Access flag or
permission faults cannot occur at level -1 because they alway involve a
descriptor at the superior level so changing those helpers is not
needed).

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/include/asm/esr.h         | 13 ++++-----
 arch/arm64/include/asm/kvm_emulate.h | 10 ++-----
 arch/arm64/mm/fault.c                | 30 +++++++-------------
 3 files changed, 18 insertions(+), 35 deletions(-)

diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
index 353fe08546cf..81606bf7d5ac 100644
--- a/arch/arm64/include/asm/esr.h
+++ b/arch/arm64/include/asm/esr.h
@@ -117,15 +117,9 @@
 #define ESR_ELx_FSC_ACCESS	(0x08)
 #define ESR_ELx_FSC_FAULT	(0x04)
 #define ESR_ELx_FSC_PERM	(0x0C)
-#define ESR_ELx_FSC_SEA_TTW0	(0x14)
-#define ESR_ELx_FSC_SEA_TTW1	(0x15)
-#define ESR_ELx_FSC_SEA_TTW2	(0x16)
-#define ESR_ELx_FSC_SEA_TTW3	(0x17)
+#define ESR_ELx_FSC_SEA_TTW(n)	(0x14 + (n))
 #define ESR_ELx_FSC_SECC	(0x18)
-#define ESR_ELx_FSC_SECC_TTW0	(0x1c)
-#define ESR_ELx_FSC_SECC_TTW1	(0x1d)
-#define ESR_ELx_FSC_SECC_TTW2	(0x1e)
-#define ESR_ELx_FSC_SECC_TTW3	(0x1f)
+#define ESR_ELx_FSC_SECC_TTW(n)	(0x1c + (n))
 
 /* ISS field definitions for Data Aborts */
 #define ESR_ELx_ISV_SHIFT	(24)
@@ -394,6 +388,9 @@ static inline bool esr_is_data_abort(unsigned long esr)
 
 static inline bool esr_fsc_is_translation_fault(unsigned long esr)
 {
+	/* Translation fault, level -1 */
+	if ((esr & ESR_ELx_FSC) == 0b101011)
+		return true;
 	return (esr & ESR_ELx_FSC_TYPE) == ESR_ELx_FSC_FAULT;
 }
 
diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index b804fe832184..6f5b41c70103 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -425,15 +425,9 @@ static __always_inline bool kvm_vcpu_abt_issea(const struct kvm_vcpu *vcpu)
 {
 	switch (kvm_vcpu_trap_get_fault(vcpu)) {
 	case ESR_ELx_FSC_EXTABT:
-	case ESR_ELx_FSC_SEA_TTW0:
-	case ESR_ELx_FSC_SEA_TTW1:
-	case ESR_ELx_FSC_SEA_TTW2:
-	case ESR_ELx_FSC_SEA_TTW3:
+	case ESR_ELx_FSC_SEA_TTW(-1) ... ESR_ELx_FSC_SEA_TTW(3):
 	case ESR_ELx_FSC_SECC:
-	case ESR_ELx_FSC_SECC_TTW0:
-	case ESR_ELx_FSC_SECC_TTW1:
-	case ESR_ELx_FSC_SECC_TTW2:
-	case ESR_ELx_FSC_SECC_TTW3:
+	case ESR_ELx_FSC_SECC_TTW(-1) ... ESR_ELx_FSC_SECC_TTW(3):
 		return true;
 	default:
 		return false;
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 55f6455a8284..60265ede48fe 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -257,16 +257,14 @@ static bool is_el1_data_abort(unsigned long esr)
 static inline bool is_el1_permission_fault(unsigned long addr, unsigned long esr,
 					   struct pt_regs *regs)
 {
-	unsigned long fsc_type = esr & ESR_ELx_FSC_TYPE;
-
 	if (!is_el1_data_abort(esr) && !is_el1_instruction_abort(esr))
 		return false;
 
-	if (fsc_type == ESR_ELx_FSC_PERM)
+	if (esr_fsc_is_permission_fault(esr))
 		return true;
 
 	if (is_ttbr0_addr(addr) && system_uses_ttbr0_pan())
-		return fsc_type == ESR_ELx_FSC_FAULT &&
+		return esr_fsc_is_translation_fault(esr) &&
 			(regs->pstate & PSR_PAN_BIT);
 
 	return false;
@@ -279,8 +277,7 @@ static bool __kprobes is_spurious_el1_translation_fault(unsigned long addr,
 	unsigned long flags;
 	u64 par, dfsc;
 
-	if (!is_el1_data_abort(esr) ||
-	    (esr & ESR_ELx_FSC_TYPE) != ESR_ELx_FSC_FAULT)
+	if (!is_el1_data_abort(esr) || !esr_fsc_is_translation_fault(esr))
 		return false;
 
 	local_irq_save(flags);
@@ -301,7 +298,7 @@ static bool __kprobes is_spurious_el1_translation_fault(unsigned long addr,
 	 * treat the translation fault as spurious.
 	 */
 	dfsc = FIELD_GET(SYS_PAR_EL1_FST, par);
-	return (dfsc & ESR_ELx_FSC_TYPE) != ESR_ELx_FSC_FAULT;
+	return !esr_fsc_is_translation_fault(dfsc);
 }
 
 static void die_kernel_fault(const char *msg, unsigned long addr,
@@ -368,11 +365,6 @@ static bool is_el1_mte_sync_tag_check_fault(unsigned long esr)
 	return false;
 }
 
-static bool is_translation_fault(unsigned long esr)
-{
-	return (esr & ESR_ELx_FSC_TYPE) == ESR_ELx_FSC_FAULT;
-}
-
 static void __do_kernel_fault(unsigned long addr, unsigned long esr,
 			      struct pt_regs *regs)
 {
@@ -405,7 +397,7 @@ static void __do_kernel_fault(unsigned long addr, unsigned long esr,
 	} else if (addr < PAGE_SIZE) {
 		msg = "NULL pointer dereference";
 	} else {
-		if (is_translation_fault(esr) &&
+		if (esr_fsc_is_translation_fault(esr) &&
 		    kfence_handle_page_fault(addr, esr & ESR_ELx_WNR, regs))
 			return;
 
@@ -782,18 +774,18 @@ static const struct fault_info fault_info[] = {
 	{ do_translation_fault,	SIGSEGV, SEGV_MAPERR,	"level 1 translation fault"	},
 	{ do_translation_fault,	SIGSEGV, SEGV_MAPERR,	"level 2 translation fault"	},
 	{ do_translation_fault,	SIGSEGV, SEGV_MAPERR,	"level 3 translation fault"	},
-	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 8"			},
+	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 0 access flag fault"	},
 	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 1 access flag fault"	},
 	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 2 access flag fault"	},
 	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 3 access flag fault"	},
-	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 12"			},
+	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 0 permission fault"	},
 	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 1 permission fault"	},
 	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 2 permission fault"	},
 	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"level 3 permission fault"	},
 	{ do_sea,		SIGBUS,  BUS_OBJERR,	"synchronous external abort"	},
 	{ do_tag_check_fault,	SIGSEGV, SEGV_MTESERR,	"synchronous tag check fault"	},
 	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 18"			},
-	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 19"			},
+	{ do_sea,		SIGKILL, SI_KERNEL,	"level -1 (translation table walk)"	},
 	{ do_sea,		SIGKILL, SI_KERNEL,	"level 0 (translation table walk)"	},
 	{ do_sea,		SIGKILL, SI_KERNEL,	"level 1 (translation table walk)"	},
 	{ do_sea,		SIGKILL, SI_KERNEL,	"level 2 (translation table walk)"	},
@@ -801,7 +793,7 @@ static const struct fault_info fault_info[] = {
 	{ do_sea,		SIGBUS,  BUS_OBJERR,	"synchronous parity or ECC error" },	// Reserved when RAS is implemented
 	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 25"			},
 	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 26"			},
-	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 27"			},
+	{ do_sea,		SIGKILL, SI_KERNEL,	"level -1 synchronous parity error (translation table walk)"	},	// Reserved when RAS is implemented
 	{ do_sea,		SIGKILL, SI_KERNEL,	"level 0 synchronous parity error (translation table walk)"	},	// Reserved when RAS is implemented
 	{ do_sea,		SIGKILL, SI_KERNEL,	"level 1 synchronous parity error (translation table walk)"	},	// Reserved when RAS is implemented
 	{ do_sea,		SIGKILL, SI_KERNEL,	"level 2 synchronous parity error (translation table walk)"	},	// Reserved when RAS is implemented
@@ -815,9 +807,9 @@ static const struct fault_info fault_info[] = {
 	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 38"			},
 	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 39"			},
 	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 40"			},
-	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 41"			},
+	{ do_bad,		SIGKILL, SI_KERNEL,	"level -1 address size fault"	},
 	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 42"			},
-	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 43"			},
+	{ do_translation_fault,	SIGSEGV, SEGV_MAPERR,	"level -1 translation fault"	},
 	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 44"			},
 	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 45"			},
 	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 46"			},
-- 
2.43.0.687.g38aa6559b0-goog


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