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Message-ID: <68d59c00-da02-b362-7bd9-a9631eca0fdd@csgroup.eu>
Date: Sat, 27 Jun 2020 08:42:31 +0200
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Hari Bathini <hbathini@...ux.ibm.com>,
Michael Ellerman <mpe@...erman.id.au>,
Andrew Morton <akpm@...ux-foundation.org>
Cc: Pingfan Liu <piliu@...hat.com>,
Kexec-ml <kexec@...ts.infradead.org>,
Petr Tesarik <ptesarik@...e.cz>,
Mahesh J Salgaonkar <mahesh@...ux.ibm.com>,
Sourabh Jain <sourabhjain@...ux.ibm.com>,
lkml <linux-kernel@...r.kernel.org>,
linuxppc-dev <linuxppc-dev@...abs.org>,
Mimi Zohar <zohar@...ux.ibm.com>,
Vivek Goyal <vgoyal@...hat.com>,
Dave Young <dyoung@...hat.com>,
Thiago Jung Bauermann <bauerman@...ux.ibm.com>,
Eric Biederman <ebiederm@...ssion.com>
Subject: Re: [PATCH 02/11] powerpc/kexec_file: mark PPC64 specific code
Le 26/06/2020 à 21:04, Hari Bathini a écrit :
> Some of the kexec_file_load code isn't PPC64 specific. Move PPC64
> specific code from kexec/file_load.c to kexec/file_load_64.c. Also,
> rename purgatory/trampoline.S to purgatory/trampoline_64.S in the
> same spirit.
At the time being, CONFIG_KEXEC_FILE depends on PPC64.
Are you planning to make it work on PPC32 as well ?
Otherwise I don't understand the purpose of this patch.
Also, what is being done in this patch seems to go far beyond what you
describe above. It is propably worth splitting in several patches with
proper explanation.
Christophe
>
> Signed-off-by: Hari Bathini <hbathini@...ux.ibm.com>
> ---
> arch/powerpc/include/asm/kexec.h | 11 +++
> arch/powerpc/kexec/Makefile | 2 -
> arch/powerpc/kexec/elf_64.c | 7 +-
> arch/powerpc/kexec/file_load.c | 37 ++--------
> arch/powerpc/kexec/file_load_64.c | 108 ++++++++++++++++++++++++++++++
> arch/powerpc/purgatory/Makefile | 4 +
> arch/powerpc/purgatory/trampoline.S | 117 --------------------------------
> arch/powerpc/purgatory/trampoline_64.S | 117 ++++++++++++++++++++++++++++++++
> 8 files changed, 248 insertions(+), 155 deletions(-)
> create mode 100644 arch/powerpc/kexec/file_load_64.c
> delete mode 100644 arch/powerpc/purgatory/trampoline.S
> create mode 100644 arch/powerpc/purgatory/trampoline_64.S
>
> diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
> index c684768..7008ea1 100644
> --- a/arch/powerpc/include/asm/kexec.h
> +++ b/arch/powerpc/include/asm/kexec.h
> @@ -114,8 +114,17 @@ int setup_purgatory(struct kimage *image, const void *slave_code,
> unsigned long fdt_load_addr);
> int setup_new_fdt(const struct kimage *image, void *fdt,
> unsigned long initrd_load_addr, unsigned long initrd_len,
> - const char *cmdline);
> + const char *cmdline, int *node);
> int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size);
> +
> +#ifdef CONFIG_PPC64
> +int setup_purgatory_ppc64(struct kimage *image, const void *slave_code,
> + const void *fdt, unsigned long kernel_load_addr,
> + unsigned long fdt_load_addr);
> +int setup_new_fdt_ppc64(const struct kimage *image, void *fdt,
> + unsigned long initrd_load_addr,
> + unsigned long initrd_len, const char *cmdline);
> +#endif /* CONFIG_PPC64 */
> #endif /* CONFIG_KEXEC_FILE */
>
> #else /* !CONFIG_KEXEC_CORE */
> diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
> index 86380c6..67c3553 100644
> --- a/arch/powerpc/kexec/Makefile
> +++ b/arch/powerpc/kexec/Makefile
> @@ -7,7 +7,7 @@ obj-y += core.o crash.o core_$(BITS).o
>
> obj-$(CONFIG_PPC32) += relocate_32.o
>
> -obj-$(CONFIG_KEXEC_FILE) += file_load.o elf_$(BITS).o
> +obj-$(CONFIG_KEXEC_FILE) += file_load.o file_load_$(BITS).o elf_$(BITS).o
>
> ifdef CONFIG_HAVE_IMA_KEXEC
> ifdef CONFIG_IMA
> diff --git a/arch/powerpc/kexec/elf_64.c b/arch/powerpc/kexec/elf_64.c
> index 3072fd6..23ad04c 100644
> --- a/arch/powerpc/kexec/elf_64.c
> +++ b/arch/powerpc/kexec/elf_64.c
> @@ -88,7 +88,8 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
> goto out;
> }
>
> - ret = setup_new_fdt(image, fdt, initrd_load_addr, initrd_len, cmdline);
> + ret = setup_new_fdt_ppc64(image, fdt, initrd_load_addr,
> + initrd_len, cmdline);
> if (ret)
> goto out;
>
> @@ -107,8 +108,8 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
> pr_debug("Loaded device tree at 0x%lx\n", fdt_load_addr);
>
> slave_code = elf_info.buffer + elf_info.proghdrs[0].p_offset;
> - ret = setup_purgatory(image, slave_code, fdt, kernel_load_addr,
> - fdt_load_addr);
> + ret = setup_purgatory_ppc64(image, slave_code, fdt, kernel_load_addr,
> + fdt_load_addr);
> if (ret)
> pr_err("Error setting up the purgatory.\n");
>
> diff --git a/arch/powerpc/kexec/file_load.c b/arch/powerpc/kexec/file_load.c
> index 143c917..99a2c4d 100644
> --- a/arch/powerpc/kexec/file_load.c
> +++ b/arch/powerpc/kexec/file_load.c
> @@ -1,6 +1,6 @@
> // SPDX-License-Identifier: GPL-2.0-only
> /*
> - * ppc64 code to implement the kexec_file_load syscall
> + * powerpc code to implement the kexec_file_load syscall
> *
> * Copyright (C) 2004 Adam Litke (agl@...ibm.com)
> * Copyright (C) 2004 IBM Corp.
> @@ -16,26 +16,10 @@
>
> #include <linux/slab.h>
> #include <linux/kexec.h>
> -#include <linux/of_fdt.h>
> #include <linux/libfdt.h>
> #include <asm/ima.h>
>
> -#define SLAVE_CODE_SIZE 256
> -
> -const struct kexec_file_ops * const kexec_file_loaders[] = {
> - &kexec_elf64_ops,
> - NULL
> -};
> -
> -int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
> - unsigned long buf_len)
> -{
> - /* We don't support crash kernels yet. */
> - if (image->type == KEXEC_TYPE_CRASH)
> - return -EOPNOTSUPP;
> -
> - return kexec_image_probe_default(image, buf, buf_len);
> -}
> +#define SLAVE_CODE_SIZE 256 /* First 0x100 bytes */
>
> /**
> * setup_purgatory - initialize the purgatory's global variables
> @@ -127,24 +111,17 @@ int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
> * @initrd_len: Size of the next initrd, or 0 if there will be none.
> * @cmdline: Command line for the next kernel, or NULL if there will
> * be none.
> + * @chosen_node: Set this output parameter to chosen_node.
> *
> * Return: 0 on success, or negative errno on error.
> */
> int setup_new_fdt(const struct kimage *image, void *fdt,
> unsigned long initrd_load_addr, unsigned long initrd_len,
> - const char *cmdline)
> + const char *cmdline, int *node)
> {
> int ret, chosen_node;
> const void *prop;
>
> - /* Remove memory reservation for the current device tree. */
> - ret = delete_fdt_mem_rsv(fdt, __pa(initial_boot_params),
> - fdt_totalsize(initial_boot_params));
> - if (ret == 0)
> - pr_debug("Removed old device tree reservation.\n");
> - else if (ret != -ENOENT)
> - return ret;
> -
> chosen_node = fdt_path_offset(fdt, "/chosen");
> if (chosen_node == -FDT_ERR_NOTFOUND) {
> chosen_node = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"),
> @@ -157,6 +134,8 @@ int setup_new_fdt(const struct kimage *image, void *fdt,
> pr_err("Malformed device tree: error reading /chosen.\n");
> return -EINVAL;
> }
> + if (node)
> + *node = chosen_node;
>
> /* Did we boot using an initrd? */
> prop = fdt_getprop(fdt, chosen_node, "linux,initrd-start", NULL);
> @@ -242,10 +221,6 @@ int setup_new_fdt(const struct kimage *image, void *fdt,
> return ret;
> }
>
> - ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
> - if (ret)
> - goto err;
> -
> return 0;
>
> err:
> diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c
> new file mode 100644
> index 0000000..e6bff960
> --- /dev/null
> +++ b/arch/powerpc/kexec/file_load_64.c
> @@ -0,0 +1,108 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * ppc64 code to implement the kexec_file_load syscall
> + *
> + * Copyright (C) 2004 Adam Litke (agl@...ibm.com)
> + * Copyright (C) 2004 IBM Corp.
> + * Copyright (C) 2004,2005 Milton D Miller II, IBM Corporation
> + * Copyright (C) 2005 R Sharada (sharada@...ibm.com)
> + * Copyright (C) 2006 Mohan Kumar M (mohan@...ibm.com)
> + * Copyright (C) 2020 IBM Corporation
> + *
> + * Based on kexec-tools' kexec-ppc64.c, kexec-elf-rel-ppc64.c, fs2dt.c.
> + * Heavily modified for the kernel by
> + * Hari Bathini <hbathini@...ux.ibm.com>.
> + */
> +
> +#include <linux/kexec.h>
> +#include <linux/of_fdt.h>
> +#include <linux/libfdt.h>
> +
> +const struct kexec_file_ops * const kexec_file_loaders[] = {
> + &kexec_elf64_ops,
> + NULL
> +};
> +
> +/**
> + * setup_purgatory_ppc64 - initialize PPC64 specific purgatory's global
> + * variables and call setup_purgatory() to initialize
> + * common global variable.
> + * @image: kexec image.
> + * @slave_code: Slave code for the purgatory.
> + * @fdt: Flattened device tree for the next kernel.
> + * @kernel_load_addr: Address where the kernel is loaded.
> + * @fdt_load_addr: Address where the flattened device tree is loaded.
> + *
> + * Returns 0 on success, negative errno on error.
> + */
> +int setup_purgatory_ppc64(struct kimage *image, const void *slave_code,
> + const void *fdt, unsigned long kernel_load_addr,
> + unsigned long fdt_load_addr)
> +{
> + int ret;
> +
> + ret = setup_purgatory(image, slave_code, fdt, kernel_load_addr,
> + fdt_load_addr);
> + if (ret)
> + pr_err("Failed to setup purgatory symbols");
> + return ret;
> +}
> +
> +/**
> + * setup_new_fdt_ppc64 - Update the flattend device-tree of the kernel
> + * being loaded.
> + * @image: kexec image being loaded.
> + * @fdt: Flattened device tree for the next kernel.
> + * @initrd_load_addr: Address where the next initrd will be loaded.
> + * @initrd_len: Size of the next initrd, or 0 if there will be none.
> + * @cmdline: Command line for the next kernel, or NULL if there will
> + * be none.
> + *
> + * Returns 0 on success, negative errno on error.
> + */
> +int setup_new_fdt_ppc64(const struct kimage *image, void *fdt,
> + unsigned long initrd_load_addr,
> + unsigned long initrd_len, const char *cmdline)
> +{
> + int chosen_node, ret;
> +
> + /* Remove memory reservation for the current device tree. */
> + ret = delete_fdt_mem_rsv(fdt, __pa(initial_boot_params),
> + fdt_totalsize(initial_boot_params));
> + if (ret == 0)
> + pr_debug("Removed old device tree reservation.\n");
> + else if (ret != -ENOENT) {
> + pr_err("Failed to remove old device-tree reservation.\n");
> + return ret;
> + }
> +
> + ret = setup_new_fdt(image, fdt, initrd_load_addr, initrd_len,
> + cmdline, &chosen_node);
> + if (ret)
> + return ret;
> +
> + ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
> + if (ret)
> + pr_err("Failed to update device-tree with linux,booted-from-kexec\n");
> +
> + return ret;
> +}
> +
> +/**
> + * arch_kexec_kernel_image_probe - Does additional handling needed to setup
> + * kexec segments.
> + * @image: kexec image being loaded.
> + * @buf: Buffer pointing to elf data.
> + * @buf_len: Length of the buffer.
> + *
> + * Returns 0 on success, negative errno on error.
> + */
> +int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
> + unsigned long buf_len)
> +{
> + /* We don't support crash kernels yet. */
> + if (image->type == KEXEC_TYPE_CRASH)
> + return -EOPNOTSUPP;
> +
> + return kexec_image_probe_default(image, buf, buf_len);
> +}
> diff --git a/arch/powerpc/purgatory/Makefile b/arch/powerpc/purgatory/Makefile
> index 7c6d8b1..348f5958 100644
> --- a/arch/powerpc/purgatory/Makefile
> +++ b/arch/powerpc/purgatory/Makefile
> @@ -2,11 +2,11 @@
>
> KASAN_SANITIZE := n
>
> -targets += trampoline.o purgatory.ro kexec-purgatory.c
> +targets += trampoline_$(BITS).o purgatory.ro kexec-purgatory.c
>
> LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined
>
> -$(obj)/purgatory.ro: $(obj)/trampoline.o FORCE
> +$(obj)/purgatory.ro: $(obj)/trampoline_$(BITS).o FORCE
> $(call if_changed,ld)
>
> quiet_cmd_bin2c = BIN2C $@
> diff --git a/arch/powerpc/purgatory/trampoline.S b/arch/powerpc/purgatory/trampoline.S
> deleted file mode 100644
> index a5a83c3..0000000
> --- a/arch/powerpc/purgatory/trampoline.S
> +++ /dev/null
> @@ -1,117 +0,0 @@
> -/* SPDX-License-Identifier: GPL-2.0-only */
> -/*
> - * kexec trampoline
> - *
> - * Based on code taken from kexec-tools and kexec-lite.
> - *
> - * Copyright (C) 2004 - 2005, Milton D Miller II, IBM Corporation
> - * Copyright (C) 2006, Mohan Kumar M, IBM Corporation
> - * Copyright (C) 2013, Anton Blanchard, IBM Corporation
> - */
> -
> -#include <asm/asm-compat.h>
> -
> - .machine ppc64
> - .balign 256
> - .globl purgatory_start
> -purgatory_start:
> - b master
> -
> - /* ABI: possible run_at_load flag at 0x5c */
> - .org purgatory_start + 0x5c
> - .globl run_at_load
> -run_at_load:
> - .long 0
> - .size run_at_load, . - run_at_load
> -
> - /* ABI: slaves start at 60 with r3=phys */
> - .org purgatory_start + 0x60
> -slave:
> - b .
> - /* ABI: end of copied region */
> - .org purgatory_start + 0x100
> - .size purgatory_start, . - purgatory_start
> -
> -/*
> - * The above 0x100 bytes at purgatory_start are replaced with the
> - * code from the kernel (or next stage) by setup_purgatory().
> - */
> -
> -master:
> - or %r1,%r1,%r1 /* low priority to let other threads catchup */
> - isync
> - mr %r17,%r3 /* save cpu id to r17 */
> - mr %r15,%r4 /* save physical address in reg15 */
> -
> - or %r3,%r3,%r3 /* ok now to high priority, lets boot */
> - lis %r6,0x1
> - mtctr %r6 /* delay a bit for slaves to catch up */
> - bdnz . /* before we overwrite 0-100 again */
> -
> - bl 0f /* Work out where we're running */
> -0: mflr %r18
> -
> - /* load device-tree address */
> - ld %r3, (dt_offset - 0b)(%r18)
> - mr %r16,%r3 /* save dt address in reg16 */
> - li %r4,20
> - LWZX_BE %r6,%r3,%r4 /* fetch __be32 version number at byte 20 */
> - cmpwi %cr0,%r6,2 /* v2 or later? */
> - blt 1f
> - li %r4,28
> - STWX_BE %r17,%r3,%r4 /* Store my cpu as __be32 at byte 28 */
> -1:
> - /* load the kernel address */
> - ld %r4,(kernel - 0b)(%r18)
> -
> - /* load the run_at_load flag */
> - /* possibly patched by kexec */
> - ld %r6,(run_at_load - 0b)(%r18)
> - /* and patch it into the kernel */
> - stw %r6,(0x5c)(%r4)
> -
> - mr %r3,%r16 /* restore dt address */
> -
> - li %r5,0 /* r5 will be 0 for kernel */
> -
> - mfmsr %r11
> - andi. %r10,%r11,1 /* test MSR_LE */
> - bne .Little_endian
> -
> - mtctr %r4 /* prepare branch to */
> - bctr /* start kernel */
> -
> -.Little_endian:
> - mtsrr0 %r4 /* prepare branch to */
> -
> - clrrdi %r11,%r11,1 /* clear MSR_LE */
> - mtsrr1 %r11
> -
> - rfid /* update MSR and start kernel */
> -
> -
> - .balign 8
> - .globl kernel
> -kernel:
> - .8byte 0x0
> - .size kernel, . - kernel
> -
> - .balign 8
> - .globl dt_offset
> -dt_offset:
> - .8byte 0x0
> - .size dt_offset, . - dt_offset
> -
> -
> - .data
> - .balign 8
> -.globl purgatory_sha256_digest
> -purgatory_sha256_digest:
> - .skip 32
> - .size purgatory_sha256_digest, . - purgatory_sha256_digest
> -
> - .balign 8
> -.globl purgatory_sha_regions
> -purgatory_sha_regions:
> - .skip 8 * 2 * 16
> - .size purgatory_sha_regions, . - purgatory_sha_regions
> diff --git a/arch/powerpc/purgatory/trampoline_64.S b/arch/powerpc/purgatory/trampoline_64.S
> new file mode 100644
> index 0000000..a5a83c3
> --- /dev/null
> +++ b/arch/powerpc/purgatory/trampoline_64.S
> @@ -0,0 +1,117 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * kexec trampoline
> + *
> + * Based on code taken from kexec-tools and kexec-lite.
> + *
> + * Copyright (C) 2004 - 2005, Milton D Miller II, IBM Corporation
> + * Copyright (C) 2006, Mohan Kumar M, IBM Corporation
> + * Copyright (C) 2013, Anton Blanchard, IBM Corporation
> + */
> +
> +#include <asm/asm-compat.h>
> +
> + .machine ppc64
> + .balign 256
> + .globl purgatory_start
> +purgatory_start:
> + b master
> +
> + /* ABI: possible run_at_load flag at 0x5c */
> + .org purgatory_start + 0x5c
> + .globl run_at_load
> +run_at_load:
> + .long 0
> + .size run_at_load, . - run_at_load
> +
> + /* ABI: slaves start at 60 with r3=phys */
> + .org purgatory_start + 0x60
> +slave:
> + b .
> + /* ABI: end of copied region */
> + .org purgatory_start + 0x100
> + .size purgatory_start, . - purgatory_start
> +
> +/*
> + * The above 0x100 bytes at purgatory_start are replaced with the
> + * code from the kernel (or next stage) by setup_purgatory().
> + */
> +
> +master:
> + or %r1,%r1,%r1 /* low priority to let other threads catchup */
> + isync
> + mr %r17,%r3 /* save cpu id to r17 */
> + mr %r15,%r4 /* save physical address in reg15 */
> +
> + or %r3,%r3,%r3 /* ok now to high priority, lets boot */
> + lis %r6,0x1
> + mtctr %r6 /* delay a bit for slaves to catch up */
> + bdnz . /* before we overwrite 0-100 again */
> +
> + bl 0f /* Work out where we're running */
> +0: mflr %r18
> +
> + /* load device-tree address */
> + ld %r3, (dt_offset - 0b)(%r18)
> + mr %r16,%r3 /* save dt address in reg16 */
> + li %r4,20
> + LWZX_BE %r6,%r3,%r4 /* fetch __be32 version number at byte 20 */
> + cmpwi %cr0,%r6,2 /* v2 or later? */
> + blt 1f
> + li %r4,28
> + STWX_BE %r17,%r3,%r4 /* Store my cpu as __be32 at byte 28 */
> +1:
> + /* load the kernel address */
> + ld %r4,(kernel - 0b)(%r18)
> +
> + /* load the run_at_load flag */
> + /* possibly patched by kexec */
> + ld %r6,(run_at_load - 0b)(%r18)
> + /* and patch it into the kernel */
> + stw %r6,(0x5c)(%r4)
> +
> + mr %r3,%r16 /* restore dt address */
> +
> + li %r5,0 /* r5 will be 0 for kernel */
> +
> + mfmsr %r11
> + andi. %r10,%r11,1 /* test MSR_LE */
> + bne .Little_endian
> +
> + mtctr %r4 /* prepare branch to */
> + bctr /* start kernel */
> +
> +.Little_endian:
> + mtsrr0 %r4 /* prepare branch to */
> +
> + clrrdi %r11,%r11,1 /* clear MSR_LE */
> + mtsrr1 %r11
> +
> + rfid /* update MSR and start kernel */
> +
> +
> + .balign 8
> + .globl kernel
> +kernel:
> + .8byte 0x0
> + .size kernel, . - kernel
> +
> + .balign 8
> + .globl dt_offset
> +dt_offset:
> + .8byte 0x0
> + .size dt_offset, . - dt_offset
> +
> +
> + .data
> + .balign 8
> +.globl purgatory_sha256_digest
> +purgatory_sha256_digest:
> + .skip 32
> + .size purgatory_sha256_digest, . - purgatory_sha256_digest
> +
> + .balign 8
> +.globl purgatory_sha_regions
> +purgatory_sha_regions:
> + .skip 8 * 2 * 16
> + .size purgatory_sha_regions, . - purgatory_sha_regions
>
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