From 7684b8582c24537dbe079a7d40e1d7e57ca56939 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Sat, 11 Jan 2020 01:03:44 +0900 Subject: bootconfig: Load boot config from the tail of initrd Load the extended boot config data from the tail of initrd image. If there is an SKC data there, it has [(u32)size][(u32)checksum] header (in really, this is a footer) at the end of initrd. If the checksum (simple sum of bytes) is match, this starts parsing it from there. Link: http://lkml.kernel.org/r/157867222435.17873.9936667353335606867.stgit@devnote2 Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- init/Kconfig | 1 + init/main.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 55 insertions(+) diff --git a/init/Kconfig b/init/Kconfig index 63450d3bbf12..ffd240fb88c3 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1217,6 +1217,7 @@ endif config BOOT_CONFIG bool "Boot config support" + depends on BLK_DEV_INITRD select LIBXBC default y help diff --git a/init/main.c b/init/main.c index 2cd736059416..59c418a57f92 100644 --- a/init/main.c +++ b/init/main.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include #include @@ -245,6 +246,58 @@ static int __init loglevel(char *str) early_param("loglevel", loglevel); +#ifdef CONFIG_BOOT_CONFIG +u32 boot_config_checksum(unsigned char *p, u32 size) +{ + u32 ret = 0; + + while (size--) + ret += *p++; + + return ret; +} + +static void __init setup_boot_config(void) +{ + u32 size, csum; + char *data, *copy; + u32 *hdr; + + if (!initrd_end) + return; + + hdr = (u32 *)(initrd_end - 8); + size = hdr[0]; + csum = hdr[1]; + + if (size >= XBC_DATA_MAX) + return; + + data = ((void *)hdr) - size; + if ((unsigned long)data < initrd_start) + return; + + if (boot_config_checksum((unsigned char *)data, size) != csum) + return; + + copy = memblock_alloc(size + 1, SMP_CACHE_BYTES); + if (!copy) { + pr_err("Failed to allocate memory for boot config\n"); + return; + } + + memcpy(copy, data, size); + copy[size] = '\0'; + + if (xbc_init(copy) < 0) + pr_err("Failed to parse boot config\n"); + else + pr_info("Load boot config: %d bytes\n", size); +} +#else +#define setup_boot_config() do { } while (0) +#endif + /* Change NUL term back to "=", to make "param" the whole string. */ static int __init repair_env_string(char *param, char *val, const char *unused, void *arg) @@ -595,6 +648,7 @@ asmlinkage __visible void __init start_kernel(void) pr_notice("%s", linux_banner); early_security_init(); setup_arch(&command_line); + setup_boot_config(); setup_command_line(command_line); setup_nr_cpu_ids(); setup_per_cpu_areas(); -- cgit v1.2.3