Messages in this thread | | | Subject | Re: [PATCH v3] powerpc/traps: Enhance readability for trap types | From | Christophe Leroy <> | Date | Fri, 9 Apr 2021 18:14:19 +0200 |
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Le 08/04/2021 à 16:07, Xiongwei Song a écrit : > From: Xiongwei Song <sxwjean@gmail.com> > > Create a new header named traps.h, define macros to list ppc interrupt > types in traps.h, replace the reference of the trap hex values with these > macros. > > Referred the hex number in arch/powerpc/kernel/exceptions-64e.S, > arch/powerpc/kernel/exceptions-64s.S and > arch/powerpc/include/asm/kvm_asm.h. > > v2-v3: > Correct the prefix of trap macros with INTERRUPT_, the previous prefix > is TRAP_, which is not precise. This is suggested by Segher Boessenkool > and Nicholas Piggin. > > v1-v2: > Define more trap macros to replace more trap hexs in code, not just for > the __show_regs function. This is suggested by Christophe Leroy. > > Signed-off-by: Xiongwei Song <sxwjean@gmail.com> > --- > arch/powerpc/include/asm/interrupt.h | 9 +++++--- > arch/powerpc/include/asm/ptrace.h | 3 ++- > arch/powerpc/include/asm/traps.h | 32 +++++++++++++++++++++++++++ > arch/powerpc/kernel/interrupt.c | 3 ++- > arch/powerpc/kernel/process.c | 5 ++++- > arch/powerpc/mm/book3s64/hash_utils.c | 5 +++-- > arch/powerpc/mm/fault.c | 21 +++++++++++------- > arch/powerpc/perf/core-book3s.c | 5 +++-- > arch/powerpc/xmon/xmon.c | 16 +++++++++++--- > 9 files changed, 78 insertions(+), 21 deletions(-) > create mode 100644 arch/powerpc/include/asm/traps.h > > diff --git a/arch/powerpc/include/asm/interrupt.h b/arch/powerpc/include/asm/interrupt.h > index 7c633896d758..5ce9898bc9a6 100644 > --- a/arch/powerpc/include/asm/interrupt.h > +++ b/arch/powerpc/include/asm/interrupt.h > @@ -8,6 +8,7 @@ > #include <asm/ftrace.h> > #include <asm/kprobes.h> > #include <asm/runlatch.h> > +#include <asm/traps.h> > > struct interrupt_state { > #ifdef CONFIG_PPC_BOOK3E_64 > @@ -59,7 +60,7 @@ static inline void interrupt_enter_prepare(struct pt_regs *regs, struct interrup > * CT_WARN_ON comes here via program_check_exception, > * so avoid recursion. > */ > - if (TRAP(regs) != 0x700) > + if (TRAP(regs) != INTERRUPT_PROGRAM) > CT_WARN_ON(ct_state() != CONTEXT_KERNEL); > } > #endif > @@ -156,7 +157,8 @@ static inline void interrupt_nmi_enter_prepare(struct pt_regs *regs, struct inte > /* Don't do any per-CPU operations until interrupt state is fixed */ > #endif > /* Allow DEC and PMI to be traced when they are soft-NMI */ > - if (TRAP(regs) != 0x900 && TRAP(regs) != 0xf00 && TRAP(regs) != 0x260) { > + if (TRAP(regs) != INTERRUPT_DECREMENTER && > + TRAP(regs) != INTERRUPT_PERFMON) {
I think too long names hinder readability, see later for suggestions.
> state->ftrace_enabled = this_cpu_get_ftrace_enabled(); > this_cpu_set_ftrace_enabled(0); > } > @@ -180,7 +182,8 @@ static inline void interrupt_nmi_exit_prepare(struct pt_regs *regs, struct inter > nmi_exit(); > > #ifdef CONFIG_PPC64 > - if (TRAP(regs) != 0x900 && TRAP(regs) != 0xf00 && TRAP(regs) != 0x260) > + if (TRAP(regs) != INTERRUPT_DECREMENTER && > + TRAP(regs) != INTERRUPT_PERFMON) > this_cpu_set_ftrace_enabled(state->ftrace_enabled); > > #ifdef CONFIG_PPC_BOOK3S_64 > diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h > index f10498e1b3f6..7a17e0365d43 100644 > --- a/arch/powerpc/include/asm/ptrace.h > +++ b/arch/powerpc/include/asm/ptrace.h > @@ -21,6 +21,7 @@ > > #include <uapi/asm/ptrace.h> > #include <asm/asm-const.h> > +#include <asm/traps.h> > > #ifndef __ASSEMBLY__ > struct pt_regs > @@ -237,7 +238,7 @@ static inline bool trap_is_unsupported_scv(struct pt_regs *regs) > > static inline bool trap_is_syscall(struct pt_regs *regs) > { > - return (trap_is_scv(regs) || TRAP(regs) == 0xc00); > + return (trap_is_scv(regs) || TRAP(regs) == INTERRUPT_SYSCALL); > } > > static inline bool trap_norestart(struct pt_regs *regs) > diff --git a/arch/powerpc/include/asm/traps.h b/arch/powerpc/include/asm/traps.h > new file mode 100644 > index 000000000000..cb416a17097c > --- /dev/null > +++ b/arch/powerpc/include/asm/traps.h > @@ -0,0 +1,32 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifndef _ASM_PPC_TRAPS_H > +#define _ASM_PPC_TRAPS_H > + > +#if defined(CONFIG_BOOKE) || defined(CONFIG_4xx) > +#define INTERRUPT_MACHINE_CHECK 0x000
I'd prefer shorted names in order to not be obliged to split lines. Here are some suggestions:
INT_MCE
> +#define INTERRUPT_CRITICAL_INPUT 0x100
INT_CRIT
> +#define INTERRUPT_ALTIVEC_UNAVAIL 0x200 > +#define INTERRUPT_PERFMON 0x260
INT_PERF
> +#define INTERRUPT_DOORBELL 0x280 > +#define INTERRUPT_DEBUG 0xd00 > +#elif defined(CONFIG_PPC_BOOK3S) > +#define INTERRUPT_SYSTEM_RESET 0x100
INT_SRESET
> +#define INTERRUPT_MACHINE_CHECK 0x200
INT_MCE
> +#define INTERRUPT_DATA_SEGMENT 0x380
INT_DSEG
> +#define INTERRUPT_INST_SEGMENT 0x480
INT_ISEG
> +#define INTERRUPT_DOORBELL 0xa00
INT_DBELL
> +#define INTERRUPT_TRACE 0xd00
INT_TRACE
> +#define INTERRUPT_H_DATA_STORAGE 0xe00 > +#define INTERRUPT_PERFMON 0xf00
INT_PERF
> +#define INTERRUPT_H_FAC_UNAVAIL 0xf80 > +#endif > + > +#define INTERRUPT_DATA_STORAGE 0x300
INT_DSI
> +#define INTERRUPT_INST_STORAGE 0x400
INT_ISI
> +#define INTERRUPT_ALIGNMENT 0x600
INT_ALIGN
> +#define INTERRUPT_PROGRAM 0x700
INT_PROG
> +#define INTERRUPT_FP_UNAVAIL 0x800
INT_FP_UNAVAIL
> +#define INTERRUPT_DECREMENTER 0x900
INT_DEC
> +#define INTERRUPT_SYSCALL 0xc00
INT_SYSCALL
> + > +#endif /* _ASM_PPC_TRAPS_H */
...
> diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c > index 0c0b1c2cfb49..641b3feef7ee 100644 > --- a/arch/powerpc/mm/fault.c > +++ b/arch/powerpc/mm/fault.c > @@ -44,6 +44,7 @@ > #include <asm/debug.h> > #include <asm/kup.h> > #include <asm/inst.h> > +#include <asm/traps.h> > > > /* > @@ -197,7 +198,7 @@ static int mm_fault_error(struct pt_regs *regs, unsigned long addr, > static bool bad_kernel_fault(struct pt_regs *regs, unsigned long error_code, > unsigned long address, bool is_write) > { > - int is_exec = TRAP(regs) == 0x400; > + int is_exec = TRAP(regs) == INTERRUPT_INST_STORAGE; > > /* NX faults set DSISR_PROTFAULT on the 8xx, DSISR_NOEXEC_OR_G on others */ > if (is_exec && (error_code & (DSISR_NOEXEC_OR_G | DSISR_KEYFAULT | > @@ -391,7 +392,7 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address, > struct vm_area_struct * vma; > struct mm_struct *mm = current->mm; > unsigned int flags = FAULT_FLAG_DEFAULT; > - int is_exec = TRAP(regs) == 0x400; > + int is_exec = TRAP(regs) == INTERRUPT_INST_STORAGE; > int is_user = user_mode(regs); > int is_write = page_fault_is_write(error_code); > vm_fault_t fault, major = 0; > @@ -588,20 +589,24 @@ void __bad_page_fault(struct pt_regs *regs, int sig) > /* kernel has accessed a bad area */ > > switch (TRAP(regs)) { > - case 0x300: > - case 0x380: > - case 0xe00: > + case INTERRUPT_DATA_STORAGE: > +#ifdef CONFIG_PPC_BOOK3S > + case INTERRUPT_DATA_SEGMENT: > + case INTERRUPT_H_DATA_STORAGE: > +#endif
It would be better to avoid #ifdefs when none where necessary before.
> pr_alert("BUG: %s on %s at 0x%08lx\n", > regs->dar < PAGE_SIZE ? "Kernel NULL pointer dereference" : > "Unable to handle kernel data access", > is_write ? "write" : "read", regs->dar); > break; > - case 0x400: > - case 0x480: > + case INTERRUPT_INST_STORAGE: > +#ifdef CONFIG_PPC_BOOK3S > + case INTERRUPT_INST_SEGMENT: > +#endif
It would be better to avoid #ifdefs when none where necessary before.
> pr_alert("BUG: Unable to handle kernel instruction fetch%s", > regs->nip < PAGE_SIZE ? " (NULL pointer?)\n" : "\n"); > break; > - case 0x600: > + case INTERRUPT_ALIGNMENT: > pr_alert("BUG: Unable to handle kernel unaligned access at 0x%08lx\n", > regs->dar); > break; > diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c > index 766f064f00fb..6e34f5bba232 100644 > --- a/arch/powerpc/perf/core-book3s.c > +++ b/arch/powerpc/perf/core-book3s.c > @@ -17,6 +17,7 @@ > #include <asm/firmware.h> > #include <asm/ptrace.h> > #include <asm/code-patching.h> > +#include <asm/traps.h> > > #ifdef CONFIG_PPC64 > #include "internal.h" > @@ -168,7 +169,7 @@ static bool regs_use_siar(struct pt_regs *regs) > * they have not been setup using perf_read_regs() and so regs->result > * is something random. > */ > - return ((TRAP(regs) == 0xf00) && regs->result); > + return ((TRAP(regs) == INTERRUPT_PERFMON) && regs->result); > } > > /* > @@ -347,7 +348,7 @@ static inline void perf_read_regs(struct pt_regs *regs) > * hypervisor samples as well as samples in the kernel with > * interrupts off hence the userspace check. > */ > - if (TRAP(regs) != 0xf00) > + if (TRAP(regs) != INTERRUPT_PERFMON) > use_siar = 0; > else if ((ppmu->flags & PPMU_NO_SIAR)) > use_siar = 0; > diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c > index bf7d69625a2e..2a4f99e64bf3 100644 > --- a/arch/powerpc/xmon/xmon.c > +++ b/arch/powerpc/xmon/xmon.c > @@ -54,6 +54,7 @@ > #include <asm/code-patching.h> > #include <asm/sections.h> > #include <asm/inst.h> > +#include <asm/traps.h> > > #ifdef CONFIG_PPC64 > #include <asm/hvcall.h> > @@ -1769,7 +1770,12 @@ static void excprint(struct pt_regs *fp) > printf(" sp: %lx\n", fp->gpr[1]); > printf(" msr: %lx\n", fp->msr); > > - if (trap == 0x300 || trap == 0x380 || trap == 0x600 || trap == 0x200) { > + if (trap == INTERRUPT_DATA_STORAGE || > +#ifdef CONFIG_PPC_BOOK3S > + trap == INTERRUPT_DATA_SEGMENT || > +#endif It would be better to avoid #ifdefs when none where necessary before.
And an #ifdef in the middle of a code line is awful for readability and maintainability.
> + trap == INTERRUPT_ALIGNMENT || > + trap == INTERRUPT_MACHINE_CHECK) { > printf(" dar: %lx\n", fp->dar); > if (trap != 0x380) > printf(" dsisr: %lx\n", fp->dsisr); > @@ -1785,7 +1791,7 @@ static void excprint(struct pt_regs *fp) > current->pid, current->comm); > } > > - if (trap == 0x700) > + if (trap == INTERRUPT_PROGRAM) > print_bug_trap(fp); > > printf(linux_banner); > @@ -1846,7 +1852,11 @@ static void prregs(struct pt_regs *fp) > printf("ctr = "REG" xer = "REG" trap = %4lx\n", > fp->ctr, fp->xer, fp->trap); > trap = TRAP(fp); > - if (trap == 0x300 || trap == 0x380 || trap == 0x600) > + if (trap == INTERRUPT_DATA_STORAGE || > +#ifdef CONFIG_PPC_BOOK3S > + trap == INTERRUPT_DATA_SEGMENT || > +#endif > + trap == INTERRUPT_ALIGNMENT)
It would be better to avoid #ifdefs when none where necessary before.
And an #ifdef in the middle of a code line is awful for readability and maintainability.
> printf("dar = "REG" dsisr = %.8lx\n", fp->dar, fp->dsisr); > } > >
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