[PATCH v4 2/9] kexec_file: Change kexec_add_buffer to take kexec_buf as argument.

Thiago Jung Bauermann
2016-07-07T19:50:06Z

Adapt all callers to the new function prototype.

In addition, change the type of kexec_buf.buffer from char * to void *.
There is no particular reason for it to be a char *, and the change
allows us to get rid of 3 existing casts to char * in the code.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
---
arch/x86/kernel/crash.c | 37 ++++++++--------
arch/x86/kernel/kexec-bzimage64.c | 48 +++++++++++----------
include/linux/kexec.h | 8 +---
kernel/kexec_file.c | 88 ++++++++++++++++++---------------------
4 files changed, 87 insertions(+), 94 deletions(-)

diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 9ef978d69c22..dc026ea361dc 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -615,9 +615,9 @@ static int determine_backup_region(u64 start, u64 end, void *arg)

int crash_load_segments(struct kimage *image)
{
- unsigned long src_start, src_sz, elf_sz;
- void *elf_addr;
int ret;
+ struct kexec_buf kbuf = { .image = image, .buf_min = 0,
+ .buf_max = ULONG_MAX, .top_down = false };

/*
* Determine and load a segment for backup area. First 640K RAM
@@ -631,43 +631,44 @@ int crash_load_segments(struct kimage *image)
if (ret < 0)
return ret;

- src_start = image->arch.backup_src_start;
- src_sz = image->arch.backup_src_sz;
-
/* Add backup segment. */
- if (src_sz) {
+ if (image->arch.backup_src_sz) {
+ kbuf.buffer = &crash_zero_bytes;
+ kbuf.bufsz = sizeof(crash_zero_bytes);
+ kbuf.memsz = image->arch.backup_src_sz;
+ kbuf.buf_align = PAGE_SIZE;
/*
* Ideally there is no source for backup segment. This is
* copied in purgatory after crash. Just add a zero filled
* segment for now to make sure checksum logic works fine.
*/
- ret = kexec_add_buffer(image, (char *)&crash_zero_bytes,
- sizeof(crash_zero_bytes), src_sz,
- PAGE_SIZE, 0, -1, 0,
- &image->arch.backup_load_addr);
+ ret = kexec_add_buffer(&kbuf);
if (ret)
return ret;
+ image->arch.backup_load_addr = kbuf.mem;
pr_debug("Loaded backup region at 0x%lx backup_start=0x%lx memsz=0x%lx\n",
- image->arch.backup_load_addr, src_start, src_sz);
+ image->arch.backup_load_addr,
+ image->arch.backup_src_start, kbuf.memsz);
}

/* Prepare elf headers and add a segment */
- ret = prepare_elf_headers(image, &elf_addr, &elf_sz);
+ ret = prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz);
if (ret)
return ret;

- image->arch.elf_headers = elf_addr;
- image->arch.elf_headers_sz = elf_sz;
+ image->arch.elf_headers = kbuf.buffer;
+ image->arch.elf_headers_sz = kbuf.bufsz;

- ret = kexec_add_buffer(image, (char *)elf_addr, elf_sz, elf_sz,
- ELF_CORE_HEADER_ALIGN, 0, -1, 0,
- &image->arch.elf_load_addr);
+ kbuf.memsz = kbuf.bufsz;
+ kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
+ ret = kexec_add_buffer(&kbuf);
if (ret) {
vfree((void *)image->arch.elf_headers);
return ret;
}
+ image->arch.elf_load_addr = kbuf.mem;
pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
- image->arch.elf_load_addr, elf_sz, elf_sz);
+ image->arch.elf_load_addr, kbuf.bufsz, kbuf.bufsz);

return ret;
}
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index f2356bda2b05..4b3a75329fb6 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -331,17 +331,17 @@ static void *bzImage64_load(struct kimage *image, char *kernel,

struct setup_header *header;
int setup_sects, kern16_size, ret = 0;
- unsigned long setup_header_size, params_cmdline_sz, params_misc_sz;
+ unsigned long setup_header_size, params_cmdline_sz;
struct boot_params *params;
unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
unsigned long purgatory_load_addr;
- unsigned long kernel_bufsz, kernel_memsz, kernel_align;
- char *kernel_buf;
struct bzimage64_data *ldata;
struct kexec_entry64_regs regs64;
void *stack;
unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset;
+ struct kexec_buf kbuf = { .image = image, .buf_max = ULONG_MAX,
+ .top_down = true };

header = (struct setup_header *)(kernel + setup_hdr_offset);
setup_sects = header->setup_sects;
@@ -402,11 +402,11 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
MAX_ELFCOREHDR_STR_LEN;
params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
- params_misc_sz = params_cmdline_sz + efi_map_sz +
+ kbuf.bufsz = params_cmdline_sz + efi_map_sz +
sizeof(struct setup_data) +
sizeof(struct efi_setup_data);

- params = kzalloc(params_misc_sz, GFP_KERNEL);
+ params = kzalloc(kbuf.bufsz, GFP_KERNEL);
if (!params)
return ERR_PTR(-ENOMEM);
efi_map_offset = params_cmdline_sz;
@@ -418,37 +418,41 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
/* Is there a limit on setup header size? */
memcpy(&params->hdr, (kernel + setup_hdr_offset), setup_header_size);

- ret = kexec_add_buffer(image, (char *)params, params_misc_sz,
- params_misc_sz, 16, MIN_BOOTPARAM_ADDR,
- ULONG_MAX, 1, &bootparam_load_addr);
+ kbuf.buffer = params;
+ kbuf.memsz = kbuf.bufsz;
+ kbuf.buf_align = 16;
+ kbuf.buf_min = MIN_BOOTPARAM_ADDR;
+ ret = kexec_add_buffer(&kbuf);
if (ret)
goto out_free_params;
+ bootparam_load_addr = kbuf.mem;
pr_debug("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
- bootparam_load_addr, params_misc_sz, params_misc_sz);
+ bootparam_load_addr, kbuf.bufsz, kbuf.bufsz);

/* Load kernel */
- kernel_buf = kernel + kern16_size;
- kernel_bufsz = kernel_len - kern16_size;
- kernel_memsz = PAGE_ALIGN(header->init_size);
- kernel_align = header->kernel_alignment;
-
- ret = kexec_add_buffer(image, kernel_buf,
- kernel_bufsz, kernel_memsz, kernel_align,
- MIN_KERNEL_LOAD_ADDR, ULONG_MAX, 1,
- &kernel_load_addr);
+ kbuf.buffer = kernel + kern16_size;
+ kbuf.bufsz = kernel_len - kern16_size;
+ kbuf.memsz = PAGE_ALIGN(header->init_size);
+ kbuf.buf_align = header->kernel_alignment;
+ kbuf.buf_min = MIN_KERNEL_LOAD_ADDR;
+ ret = kexec_add_buffer(&kbuf);
if (ret)
goto out_free_params;
+ kernel_load_addr = kbuf.mem;

pr_debug("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
- kernel_load_addr, kernel_memsz, kernel_memsz);
+ kernel_load_addr, kbuf.bufsz, kbuf.memsz);

/* Load initrd high */
if (initrd) {
- ret = kexec_add_buffer(image, initrd, initrd_len, initrd_len,
- PAGE_SIZE, MIN_INITRD_LOAD_ADDR,
- ULONG_MAX, 1, &initrd_load_addr);
+ kbuf.buffer = initrd;
+ kbuf.bufsz = kbuf.memsz = initrd_len;
+ kbuf.buf_align = PAGE_SIZE;
+ kbuf.buf_min = MIN_INITRD_LOAD_ADDR;
+ ret = kexec_add_buffer(&kbuf);
if (ret)
goto out_free_params;
+ initrd_load_addr = kbuf.mem;

pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
initrd_load_addr, initrd_len, initrd_len);
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 2549a99a748c..ff5fa7707bd7 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -161,7 +161,7 @@ struct kexec_file_ops {
*/
struct kexec_buf {
struct kimage *image;
- char *buffer;
+ void *buffer;
unsigned long bufsz;
unsigned long mem;
unsigned long memsz;
@@ -173,6 +173,7 @@ struct kexec_buf {

int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
int (*func)(u64, u64, void *));
+extern int kexec_add_buffer(struct kexec_buf *kbuf);
#endif /* CONFIG_KEXEC_FILE */

struct kimage {
@@ -237,11 +238,6 @@ extern asmlinkage long sys_kexec_load(unsigned long entry,
struct kexec_segment __user *segments,
unsigned long flags);
extern int kernel_kexec(void);
-extern int kexec_add_buffer(struct kimage *image, char *buffer,
- unsigned long bufsz, unsigned long memsz,
- unsigned long buf_align, unsigned long buf_min,
- unsigned long buf_max, bool top_down,
- unsigned long *load_addr);
extern struct page *kimage_alloc_control_pages(struct kimage *image,
unsigned int order);
extern int kexec_load_purgatory(struct kimage *image, unsigned long min,
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 9c0c565a08db..82ccfc4ee97e 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -449,25 +449,27 @@ int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
}

-/*
- * Helper function for placing a buffer in a kexec segment. This assumes
- * that kexec_mutex is held.
+/**
+ * kexec_add_buffer - place a buffer in a kexec segment
+ * @kbuf: Buffer contents and memory parameters.
+ *
+ * This function assumes that kexec_mutex is held.
+ * On successful return, @kbuf->mem will have the physical address of
+ * the buffer in memory.
+ *
+ * Return: 0 on success, negative errno on error.
*/
-int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz,
- unsigned long memsz, unsigned long buf_align,
- unsigned long buf_min, unsigned long buf_max,
- bool top_down, unsigned long *load_addr)
+int kexec_add_buffer(struct kexec_buf *kbuf)
{

struct kexec_segment *ksegment;
- struct kexec_buf buf, *kbuf;
int ret;

/* Currently adding segment this way is allowed only in file mode */
- if (!image->file_mode)
+ if (!kbuf->image->file_mode)
return -EINVAL;

- if (image->nr_segments >= KEXEC_SEGMENT_MAX)
+ if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX)
return -EINVAL;

/*
@@ -477,22 +479,14 @@ int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz,
* logic goes through list of segments to make sure there are
* no destination overlaps.
*/
- if (!list_empty(&image->control_pages)) {
+ if (!list_empty(&kbuf->image->control_pages)) {
WARN_ON(1);
return -EINVAL;
}

- memset(&buf, 0, sizeof(struct kexec_buf));
- kbuf = &buf;
- kbuf->image = image;
- kbuf->buffer = buffer;
- kbuf->bufsz = bufsz;
-
- kbuf->memsz = ALIGN(memsz, PAGE_SIZE);
- kbuf->buf_align = max(buf_align, PAGE_SIZE);
- kbuf->buf_min = buf_min;
- kbuf->buf_max = buf_max;
- kbuf->top_down = top_down;
+ /* Ensure minimum alignment needed for segments. */
+ kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
+ kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);

/* Walk the RAM ranges and allocate a suitable range for the buffer */
ret = arch_kexec_walk_mem(kbuf, locate_mem_hole_callback);
@@ -502,13 +496,12 @@ int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz,
}

/* Found a suitable memory range */
- ksegment = &image->segment[image->nr_segments];
+ ksegment = &kbuf->image->segment[kbuf->image->nr_segments];
ksegment->kbuf = kbuf->buffer;
ksegment->bufsz = kbuf->bufsz;
ksegment->mem = kbuf->mem;
ksegment->memsz = kbuf->memsz;
- image->nr_segments++;
- *load_addr = ksegment->mem;
+ kbuf->image->nr_segments++;
return 0;
}

@@ -630,13 +623,15 @@ static int __kexec_load_purgatory(struct kimage *image, unsigned long min,
unsigned long max, int top_down)
{
struct purgatory_info *pi = &image->purgatory_info;
- unsigned long align, buf_align, bss_align, buf_sz, bss_sz, bss_pad;
- unsigned long memsz, entry, load_addr, curr_load_addr, bss_addr, offset;
+ unsigned long align, bss_align, bss_sz, bss_pad;
+ unsigned long entry, load_addr, curr_load_addr, bss_addr, offset;
unsigned char *buf_addr, *src;
int i, ret = 0, entry_sidx = -1;
const Elf_Shdr *sechdrs_c;
Elf_Shdr *sechdrs = NULL;
- void *purgatory_buf = NULL;
+ struct kexec_buf kbuf = { .image = image, .bufsz = 0, .buf_align = 1,
+ .buf_min = min, .buf_max = max,
+ .top_down = top_down };

/*
* sechdrs_c points to section headers in purgatory and are read
@@ -702,9 +697,7 @@ static int __kexec_load_purgatory(struct kimage *image, unsigned long min,
}

/* Determine how much memory is needed to load relocatable object. */
- buf_align = 1;
bss_align = 1;
- buf_sz = 0;
bss_sz = 0;

for (i = 0; i < pi->ehdr->e_shnum; i++) {
@@ -713,10 +706,10 @@ static int __kexec_load_purgatory(struct kimage *image, unsigned long min,

align = sechdrs[i].sh_addralign;
if (sechdrs[i].sh_type != SHT_NOBITS) {
- if (buf_align < align)
- buf_align = align;
- buf_sz = ALIGN(buf_sz, align);
- buf_sz += sechdrs[i].sh_size;
+ if (kbuf.buf_align < align)
+ kbuf.buf_align = align;
+ kbuf.bufsz = ALIGN(kbuf.bufsz, align);
+ kbuf.bufsz += sechdrs[i].sh_size;
} else {
/* bss section */
if (bss_align < align)
@@ -728,32 +721,31 @@ static int __kexec_load_purgatory(struct kimage *image, unsigned long min,

/* Determine the bss padding required to align bss properly */
bss_pad = 0;
- if (buf_sz & (bss_align - 1))
- bss_pad = bss_align - (buf_sz & (bss_align - 1));
+ if (kbuf.bufsz & (bss_align - 1))
+ bss_pad = bss_align - (kbuf.bufsz & (bss_align - 1));

- memsz = buf_sz + bss_pad + bss_sz;
+ kbuf.memsz = kbuf.bufsz + bss_pad + bss_sz;

/* Allocate buffer for purgatory */
- purgatory_buf = vzalloc(buf_sz);
- if (!purgatory_buf) {
+ kbuf.buffer = vzalloc(kbuf.bufsz);
+ if (!kbuf.buffer) {
ret = -ENOMEM;
goto out;
}

- if (buf_align < bss_align)
- buf_align = bss_align;
+ if (kbuf.buf_align < bss_align)
+ kbuf.buf_align = bss_align;

/* Add buffer to segment list */
- ret = kexec_add_buffer(image, purgatory_buf, buf_sz, memsz,
- buf_align, min, max, top_down,
- &pi->purgatory_load_addr);
+ ret = kexec_add_buffer(&kbuf);
if (ret)
goto out;
+ pi->purgatory_load_addr = kbuf.mem;

/* Load SHF_ALLOC sections */
- buf_addr = purgatory_buf;
+ buf_addr = kbuf.buffer;
load_addr = curr_load_addr = pi->purgatory_load_addr;
- bss_addr = load_addr + buf_sz + bss_pad;
+ bss_addr = load_addr + kbuf.bufsz + bss_pad;

for (i = 0; i < pi->ehdr->e_shnum; i++) {
if (!(sechdrs[i].sh_flags & SHF_ALLOC))
@@ -799,11 +791,11 @@ static int __kexec_load_purgatory(struct kimage *image, unsigned long min,
* Used later to identify which section is purgatory and skip it
* from checksumming.
*/
- pi->purgatory_buf = purgatory_buf;
+ pi->purgatory_buf = kbuf.buffer;
return ret;
out:
vfree(sechdrs);
- vfree(purgatory_buf);
+ vfree(kbuf.buffer);
return ret;
}

--
1.9.1