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authorPhilipp Rudo <prudo@linux.vnet.ibm.com>2017-06-19 10:45:33 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2018-04-16 09:10:22 +0200
commit71406883fd35794d573b3085433c41d0a3bf6c21 (patch)
tree757865f09f0b8a41357c2c1ec7b1df915b057cbf
parent840798a1f52994c172270893bd2ec6013cc92e40 (diff)
s390/kexec_file: Add kexec_file_load system call
This patch adds the kexec_file_load system call to s390 as well as the arch specific functions common code requires to work. Loaders for the different file types will be added later. Signed-off-by: Philipp Rudo <prudo@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
-rw-r--r--arch/s390/Kconfig13
-rw-r--r--arch/s390/configs/default_defconfig1
-rw-r--r--arch/s390/kernel/Makefile2
-rw-r--r--arch/s390/kernel/compat_wrapper.c1
-rw-r--r--arch/s390/kernel/machine_kexec_file.c126
-rw-r--r--arch/s390/kernel/syscalls/syscall.tbl1
6 files changed, 144 insertions, 0 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 5b8d0859b317..3223ce0680c0 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -51,6 +51,19 @@ config KEXEC
def_bool y
select KEXEC_CORE
+config KEXEC_FILE
+ bool "kexec file based system call"
+ select KEXEC_CORE
+ select BUILD_BIN2C
+ depends on CRYPTO
+ depends on CRYPTO_SHA256
+ depends on CRYPTO_SHA256_S390
+ ---help---
+ This is new version of kexec system call. This system call is
+ file based and takes file descriptors as system call argument
+ for kernel and initramfs as opposed to list of segments as
+ accepted by previous system call.
+
config ARCH_HAS_KEXEC_PURGATORY
def_bool y
depends on KEXEC_FILE
diff --git a/arch/s390/configs/default_defconfig b/arch/s390/configs/default_defconfig
index 5af8458951cf..2310315b0744 100644
--- a/arch/s390/configs/default_defconfig
+++ b/arch/s390/configs/default_defconfig
@@ -719,3 +719,4 @@ CONFIG_APPLDATA_BASE=y
CONFIG_KVM=m
CONFIG_KVM_S390_UCONTROL=y
CONFIG_VHOST_NET=m
+CONFIG_KEXEC_FILE=y
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index b06a6f79c1ec..35bec1ab84e3 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -82,6 +82,8 @@ obj-$(CONFIG_FUNCTION_TRACER) += mcount.o ftrace.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_UPROBES) += uprobes.o
+obj-$(CONFIG_KEXEC_FILE) += machine_kexec_file.o
+
obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_cpum_cf.o perf_cpum_sf.o
obj-$(CONFIG_PERF_EVENTS) += perf_cpum_cf_events.o perf_regs.o
diff --git a/arch/s390/kernel/compat_wrapper.c b/arch/s390/kernel/compat_wrapper.c
index 11e9d8b5c1b0..607c5e9fba3d 100644
--- a/arch/s390/kernel/compat_wrapper.c
+++ b/arch/s390/kernel/compat_wrapper.c
@@ -182,3 +182,4 @@ COMPAT_SYSCALL_WRAP6(copy_file_range, int, fd_in, loff_t __user *, off_in, int,
COMPAT_SYSCALL_WRAP2(s390_guarded_storage, int, command, struct gs_cb *, gs_cb);
COMPAT_SYSCALL_WRAP5(statx, int, dfd, const char __user *, path, unsigned, flags, unsigned, mask, struct statx __user *, buffer);
COMPAT_SYSCALL_WRAP4(s390_sthyi, unsigned long, code, void __user *, info, u64 __user *, rc, unsigned long, flags);
+COMPAT_SYSCALL_WRAP5(kexec_file_load, int, kernel_fd, int, initrd_fd, unsigned long, cmdline_len, const char __user *, cmdline_ptr, unsigned long, flags)
diff --git a/arch/s390/kernel/machine_kexec_file.c b/arch/s390/kernel/machine_kexec_file.c
new file mode 100644
index 000000000000..d9b4f9d23e9f
--- /dev/null
+++ b/arch/s390/kernel/machine_kexec_file.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * s390 code for kexec_file_load system call
+ *
+ * Copyright IBM Corp. 2018
+ *
+ * Author(s): Philipp Rudo <prudo@linux.vnet.ibm.com>
+ */
+
+#include <linux/elf.h>
+#include <linux/kexec.h>
+#include <asm/setup.h>
+
+const struct kexec_file_ops * const kexec_file_loaders[] = {
+ NULL,
+};
+
+/*
+ * The kernel is loaded to a fixed location. Turn off kexec_locate_mem_hole
+ * and provide kbuf->mem by hand.
+ */
+int arch_kexec_walk_mem(struct kexec_buf *kbuf,
+ int (*func)(struct resource *, void *))
+{
+ return 1;
+}
+
+int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
+ Elf_Shdr *section,
+ const Elf_Shdr *relsec,
+ const Elf_Shdr *symtab)
+{
+ Elf_Rela *relas;
+ int i;
+
+ relas = (void *)pi->ehdr + relsec->sh_offset;
+
+ for (i = 0; i < relsec->sh_size / sizeof(*relas); i++) {
+ const Elf_Sym *sym; /* symbol to relocate */
+ unsigned long addr; /* final location after relocation */
+ unsigned long val; /* relocated symbol value */
+ void *loc; /* tmp location to modify */
+
+ sym = (void *)pi->ehdr + symtab->sh_offset;
+ sym += ELF64_R_SYM(relas[i].r_info);
+
+ if (sym->st_shndx == SHN_UNDEF)
+ return -ENOEXEC;
+
+ if (sym->st_shndx == SHN_COMMON)
+ return -ENOEXEC;
+
+ if (sym->st_shndx >= pi->ehdr->e_shnum &&
+ sym->st_shndx != SHN_ABS)
+ return -ENOEXEC;
+
+ loc = pi->purgatory_buf;
+ loc += section->sh_offset;
+ loc += relas[i].r_offset;
+
+ val = sym->st_value;
+ if (sym->st_shndx != SHN_ABS)
+ val += pi->sechdrs[sym->st_shndx].sh_addr;
+ val += relas[i].r_addend;
+
+ addr = section->sh_addr + relas[i].r_offset;
+
+ switch (ELF64_R_TYPE(relas[i].r_info)) {
+ case R_390_8: /* Direct 8 bit. */
+ *(u8 *)loc = val;
+ break;
+ case R_390_12: /* Direct 12 bit. */
+ *(u16 *)loc &= 0xf000;
+ *(u16 *)loc |= val & 0xfff;
+ break;
+ case R_390_16: /* Direct 16 bit. */
+ *(u16 *)loc = val;
+ break;
+ case R_390_20: /* Direct 20 bit. */
+ *(u32 *)loc &= 0xf00000ff;
+ *(u32 *)loc |= (val & 0xfff) << 16; /* DL */
+ *(u32 *)loc |= (val & 0xff000) >> 4; /* DH */
+ break;
+ case R_390_32: /* Direct 32 bit. */
+ *(u32 *)loc = val;
+ break;
+ case R_390_64: /* Direct 64 bit. */
+ *(u64 *)loc = val;
+ break;
+ case R_390_PC16: /* PC relative 16 bit. */
+ *(u16 *)loc = (val - addr);
+ break;
+ case R_390_PC16DBL: /* PC relative 16 bit shifted by 1. */
+ *(u16 *)loc = (val - addr) >> 1;
+ break;
+ case R_390_PC32DBL: /* PC relative 32 bit shifted by 1. */
+ *(u32 *)loc = (val - addr) >> 1;
+ break;
+ case R_390_PC32: /* PC relative 32 bit. */
+ *(u32 *)loc = (val - addr);
+ break;
+ case R_390_PC64: /* PC relative 64 bit. */
+ *(u64 *)loc = (val - addr);
+ break;
+ default:
+ break;
+ }
+ }
+ return 0;
+}
+
+int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
+ unsigned long buf_len)
+{
+ /* A kernel must be at least large enough to contain head.S. During
+ * load memory in head.S will be accessed, e.g. to register the next
+ * command line. If the next kernel were smaller the current kernel
+ * will panic at load.
+ *
+ * 0x11000 = sizeof(head.S)
+ */
+ if (buf_len < 0x11000)
+ return -ENOEXEC;
+
+ return kexec_image_probe_default(image, buf, buf_len);
+}
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index b38d48464368..8b210ead7956 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -388,3 +388,4 @@
378 common s390_guarded_storage sys_s390_guarded_storage compat_sys_s390_guarded_storage
379 common statx sys_statx compat_sys_statx
380 common s390_sthyi sys_s390_sthyi compat_sys_s390_sthyi
+381 common kexec_file_load sys_kexec_file_load compat_sys_kexec_file_load