Re: [PATCH v4 3/5] powerpc/fadump: remove dependency with CONFIG_KEXEC

From: Mahesh Jagannath Salgaonkar
Date: Fri Jan 13 2017 - 06:27:54 EST


On 01/05/2017 11:02 PM, Hari Bathini wrote:
> Now that crashkernel parameter parsing and vmcoreinfo related code is
> moved under CONFIG_CRASH_CORE instead of CONFIG_KEXEC_CORE, remove
> dependency with CONFIG_KEXEC for CONFIG_FA_DUMP. While here, get rid
> of definitions of fadump_append_elf_note() & fadump_final_note()
> functions to reuse similar functions compiled under CONFIG_CRASH_CORE.
>
> Signed-off-by: Hari Bathini <hbathini@xxxxxxxxxxxxxxxxxx>

Reviewed-by: Mahesh Salgaonkar <mahesh@xxxxxxxxxxxxxxxxxx>

> ---
> arch/powerpc/Kconfig | 10 ++++++----
> arch/powerpc/include/asm/fadump.h | 2 ++
> arch/powerpc/kernel/crash.c | 2 --
> arch/powerpc/kernel/fadump.c | 34 +++-------------------------------
> arch/powerpc/kernel/setup-common.c | 5 +++++
> 5 files changed, 16 insertions(+), 37 deletions(-)
>
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index a8ee573..b9726be 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -513,21 +513,23 @@ config RELOCATABLE_TEST
> relocation code.
>
> config CRASH_DUMP
> - bool "Build a kdump crash kernel"
> + bool "Build a dump capture kernel"
> depends on PPC64 || 6xx || FSL_BOOKE || (44x && !SMP)
> select RELOCATABLE if (PPC64 && !COMPILE_TEST) || 44x || FSL_BOOKE
> help
> - Build a kernel suitable for use as a kdump capture kernel.
> + Build a kernel suitable for use as a dump capture kernel.
> The same kernel binary can be used as production kernel and dump
> capture kernel.
>
> config FA_DUMP
> bool "Firmware-assisted dump"
> - depends on PPC64 && PPC_RTAS && CRASH_DUMP && KEXEC_CORE
> + depends on PPC64 && PPC_RTAS
> + select CRASH_CORE
> + select CRASH_DUMP
> help
> A robust mechanism to get reliable kernel crash dump with
> assistance from firmware. This approach does not use kexec,
> - instead firmware assists in booting the kdump kernel
> + instead firmware assists in booting the capture kernel
> while preserving memory contents. Firmware-assisted dump
> is meant to be a kdump replacement offering robustness and
> speed not possible without system firmware assistance.
> diff --git a/arch/powerpc/include/asm/fadump.h b/arch/powerpc/include/asm/fadump.h
> index 0031806..60b9108 100644
> --- a/arch/powerpc/include/asm/fadump.h
> +++ b/arch/powerpc/include/asm/fadump.h
> @@ -73,6 +73,8 @@
> reg_entry++; \
> })
>
> +extern int crashing_cpu;
> +
> /* Kernel Dump section info */
> struct fadump_section {
> __be32 request_flag;
> diff --git a/arch/powerpc/kernel/crash.c b/arch/powerpc/kernel/crash.c
> index 47b63de..cbabb5a 100644
> --- a/arch/powerpc/kernel/crash.c
> +++ b/arch/powerpc/kernel/crash.c
> @@ -43,8 +43,6 @@
> #define IPI_TIMEOUT 10000
> #define REAL_MODE_TIMEOUT 10000
>
> -/* This keeps a track of which one is the crashing cpu. */
> -int crashing_cpu = -1;
> static int time_to_dump;
>
> #define CRASH_HANDLER_MAX 3
> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
> index 8f0c7c5..db0b339 100644
> --- a/arch/powerpc/kernel/fadump.c
> +++ b/arch/powerpc/kernel/fadump.c
> @@ -486,34 +486,6 @@ fadump_read_registers(struct fadump_reg_entry *reg_entry, struct pt_regs *regs)
> return reg_entry;
> }
>
> -static u32 *fadump_append_elf_note(u32 *buf, char *name, unsigned type,
> - void *data, size_t data_len)
> -{
> - struct elf_note note;
> -
> - note.n_namesz = strlen(name) + 1;
> - note.n_descsz = data_len;
> - note.n_type = type;
> - memcpy(buf, &note, sizeof(note));
> - buf += (sizeof(note) + 3)/4;
> - memcpy(buf, name, note.n_namesz);
> - buf += (note.n_namesz + 3)/4;
> - memcpy(buf, data, note.n_descsz);
> - buf += (note.n_descsz + 3)/4;
> -
> - return buf;
> -}
> -
> -static void fadump_final_note(u32 *buf)
> -{
> - struct elf_note note;
> -
> - note.n_namesz = 0;
> - note.n_descsz = 0;
> - note.n_type = 0;
> - memcpy(buf, &note, sizeof(note));
> -}
> -
> static u32 *fadump_regs_to_elf_notes(u32 *buf, struct pt_regs *regs)
> {
> struct elf_prstatus prstatus;
> @@ -524,8 +496,8 @@ static u32 *fadump_regs_to_elf_notes(u32 *buf, struct pt_regs *regs)
> * prstatus.pr_pid = ????
> */
> elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
> - buf = fadump_append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
> - &prstatus, sizeof(prstatus));
> + buf = append_elf_note(buf, CRASH_CORE_NOTE_NAME, NT_PRSTATUS,
> + &prstatus, sizeof(prstatus));
> return buf;
> }
>
> @@ -666,7 +638,7 @@ static int __init fadump_build_cpu_notes(const struct fadump_mem_struct *fdm)
> note_buf = fadump_regs_to_elf_notes(note_buf, &regs);
> }
> }
> - fadump_final_note(note_buf);
> + final_note(note_buf);
>
> if (fdh) {
> pr_debug("Updating elfcore header (%llx) with cpu notes\n",
> diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
> index f516ac5..60badb1 100644
> --- a/arch/powerpc/kernel/setup-common.c
> +++ b/arch/powerpc/kernel/setup-common.c
> @@ -116,6 +116,11 @@ int ppc_do_canonicalize_irqs;
> EXPORT_SYMBOL(ppc_do_canonicalize_irqs);
> #endif
>
> +#ifdef CONFIG_CRASH_CORE
> +/* This keeps a track of which one is the crashing cpu. */
> +int crashing_cpu = -1;
> +#endif
> +
> /* also used by kexec */
> void machine_shutdown(void)
> {
>