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Message-ID: <70ece993-12bd-335c-d246-914564eb51dd@csgroup.eu>
Date: Fri, 9 Apr 2021 18:14:19 +0200
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Xiongwei Song <sxwjean@...com>, mpe@...erman.id.au,
benh@...nel.crashing.org, paulus@...ba.org, oleg@...hat.com,
npiggin@...il.com, aneesh.kumar@...ux.ibm.com,
ravi.bangoria@...ux.ibm.com, mikey@...ling.org,
haren@...ux.ibm.com, akpm@...ux-foundation.org, rppt@...nel.org,
jniethe5@...il.com, atrajeev@...ux.vnet.ibm.com,
maddy@...ux.ibm.com, peterz@...radead.org, kjain@...ux.ibm.com,
kan.liang@...ux.intel.com, aik@...abs.ru, alistair@...ple.id.au,
pmladek@...e.com, john.ogness@...utronix.de
Cc: linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
Xiongwei Song <sxwjean@...il.com>
Subject: Re: [PATCH v3] powerpc/traps: Enhance readability for trap types
Le 08/04/2021 à 16:07, Xiongwei Song a écrit :
> From: Xiongwei Song <sxwjean@...il.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@...il.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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