[RFC PATCH 1/4] powerpc: Optimize register usage for esr register
From: <hidden>
Date: 2021-07-26 14:31:38
From: Xiongwei Song <redacted> Create an anonymous union for dsisr and esr regsiters, we can reference esr to get the exception detail when CONFIG_4xx=y or CONFIG_BOOKE=y. Otherwise, reference dsisr. This makes code more clear. Signed-off-by: Xiongwei Song <redacted> --- arch/powerpc/include/asm/ptrace.h | 5 ++++- arch/powerpc/include/uapi/asm/ptrace.h | 5 ++++- arch/powerpc/kernel/process.c | 2 +- arch/powerpc/kernel/ptrace/ptrace.c | 2 ++ arch/powerpc/kernel/traps.c | 2 +- arch/powerpc/mm/fault.c | 16 ++++++++++++++-- arch/powerpc/platforms/44x/machine_check.c | 4 ++-- arch/powerpc/platforms/4xx/machine_check.c | 2 +- 8 files changed, 29 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index 3e5d470a6155..c252d04b1206 100644
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h@@ -44,7 +44,10 @@ struct pt_regs #endif unsigned long trap; unsigned long dar; - unsigned long dsisr; + union { + unsigned long dsisr; + unsigned long esr; + }; unsigned long result; }; };
diff --git a/arch/powerpc/include/uapi/asm/ptrace.h b/arch/powerpc/include/uapi/asm/ptrace.h
index 7004cfea3f5f..e357288b5f34 100644
--- a/arch/powerpc/include/uapi/asm/ptrace.h
+++ b/arch/powerpc/include/uapi/asm/ptrace.h@@ -53,7 +53,10 @@ struct pt_regs /* N.B. for critical exceptions on 4xx, the dar and dsisr fields are overloaded to hold srr0 and srr1. */ unsigned long dar; /* Fault registers */ - unsigned long dsisr; /* on 4xx/Book-E used for ESR */ + union { + unsigned long dsisr; /* on Book-S used for DSISR */ + unsigned long esr; /* on 4xx/Book-E used for ESR */ + }; unsigned long result; /* Result of a system call */ };
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 185beb290580..f74af8f9133c 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c@@ -1499,7 +1499,7 @@ static void __show_regs(struct pt_regs *regs) trap == INTERRUPT_DATA_STORAGE || trap == INTERRUPT_ALIGNMENT) { if (IS_ENABLED(CONFIG_4xx) || IS_ENABLED(CONFIG_BOOKE)) - pr_cont("DEAR: "REG" ESR: "REG" ", regs->dar, regs->dsisr); + pr_cont("DEAR: "REG" ESR: "REG" ", regs->dar, regs->esr); else pr_cont("DAR: "REG" DSISR: %08lx ", regs->dar, regs->dsisr); }
diff --git a/arch/powerpc/kernel/ptrace/ptrace.c b/arch/powerpc/kernel/ptrace/ptrace.c
index 0a0a33eb0d28..00789ad2c4a3 100644
--- a/arch/powerpc/kernel/ptrace/ptrace.c
+++ b/arch/powerpc/kernel/ptrace/ptrace.c@@ -375,6 +375,8 @@ void __init pt_regs_check(void) offsetof(struct user_pt_regs, dar)); BUILD_BUG_ON(offsetof(struct pt_regs, dsisr) != offsetof(struct user_pt_regs, dsisr)); + BUILD_BUG_ON(offsetof(struct pt_regs, esr) != + offsetof(struct user_pt_regs, esr)); BUILD_BUG_ON(offsetof(struct pt_regs, result) != offsetof(struct user_pt_regs, result));
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index dfbce527c98e..2164f5705a0b 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c@@ -562,7 +562,7 @@ static inline int check_io_access(struct pt_regs *regs) #ifdef CONFIG_PPC_ADV_DEBUG_REGS /* On 4xx, the reason for the machine check or program exception is in the ESR. */ -#define get_reason(regs) ((regs)->dsisr) +#define get_reason(regs) ((regs)->esr) #define REASON_FP ESR_FP #define REASON_ILLEGAL (ESR_PIL | ESR_PUO) #define REASON_PRIVILEGED ESR_PPR
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index a8d0ce85d39a..62953d4e7c93 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c@@ -541,7 +541,11 @@ static __always_inline void __do_page_fault(struct pt_regs *regs) { long err; - err = ___do_page_fault(regs, regs->dar, regs->dsisr); + if (IS_ENABLED(CONFIG_4xx) || IS_ENABLED(CONFIG_BOOKE)) + err = ___do_page_fault(regs, regs->dar, regs->esr); + else + err = ___do_page_fault(regs, regs->dar, regs->dsisr); + if (unlikely(err)) bad_page_fault(regs, err); }
@@ -567,7 +571,15 @@ NOKPROBE_SYMBOL(hash__do_page_fault); */ static void __bad_page_fault(struct pt_regs *regs, int sig) { - int is_write = page_fault_is_write(regs->dsisr); + unsigned long err_reg; + int is_write; + + if (IS_ENABLED(CONFIG_4xx) || IS_ENABLED(CONFIG_BOOKE)) + err_reg = regs->esr; + else + err_reg = regs->dsisr; + + is_write = page_fault_is_write(err_reg); /* kernel has accessed a bad area */
diff --git a/arch/powerpc/platforms/44x/machine_check.c b/arch/powerpc/platforms/44x/machine_check.c
index a5c898bb9bab..5d19daacd78a 100644
--- a/arch/powerpc/platforms/44x/machine_check.c
+++ b/arch/powerpc/platforms/44x/machine_check.c@@ -11,7 +11,7 @@ int machine_check_440A(struct pt_regs *regs) { - unsigned long reason = regs->dsisr; + unsigned long reason = regs->esr; printk("Machine check in kernel mode.\n"); if (reason & ESR_IMCP){
@@ -48,7 +48,7 @@ int machine_check_440A(struct pt_regs *regs) #ifdef CONFIG_PPC_47x int machine_check_47x(struct pt_regs *regs) { - unsigned long reason = regs->dsisr; + unsigned long reason = regs->esr; u32 mcsr; printk(KERN_ERR "Machine check in kernel mode.\n");
diff --git a/arch/powerpc/platforms/4xx/machine_check.c b/arch/powerpc/platforms/4xx/machine_check.c
index a71c29892a91..a905da1d6f41 100644
--- a/arch/powerpc/platforms/4xx/machine_check.c
+++ b/arch/powerpc/platforms/4xx/machine_check.c@@ -10,7 +10,7 @@ int machine_check_4xx(struct pt_regs *regs) { - unsigned long reason = regs->dsisr; + unsigned long reason = regs->esr; if (reason & ESR_IMCP) { printk("Instruction");
--
2.30.2