[RFC PATCH v3 03/19] skc: Add a boot setup routine from cmdline

From: Masami Hiramatsu
Date: Sun Aug 25 2019 - 23:16:23 EST


Add a boot setup routine from cmdline option "skc=ADDR,SIZE".
Bootloader has to setup this cmdline option when it loads
the skc file on memory. The ADDR must be a physical address.

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
Documentation/admin-guide/kernel-parameters.txt | 5 ++
init/main.c | 54 +++++++++++++++++++++++
2 files changed, 59 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 47d981a86e2f..9a955b1bd1bf 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4273,6 +4273,11 @@
simeth= [IA-64]
simscsi=

+ skc=paddr,size [SKC]
+ Pass the physical memory address and size of loaded
+ supplemental kernel cmdline (SKC) text. This will
+ be treated by bootloader which loads the SKC file.
+
slram= [HW,MTD]

slab_nomerge [MM]
diff --git a/init/main.c b/init/main.c
index 96f8d5af52d6..d06eb3d63b77 100644
--- a/init/main.c
+++ b/init/main.c
@@ -36,6 +36,7 @@
#include <linux/kernel_stat.h>
#include <linux/start_kernel.h>
#include <linux/security.h>
+#include <linux/skc.h>
#include <linux/smp.h>
#include <linux/profile.h>
#include <linux/rcupdate.h>
@@ -245,6 +246,58 @@ static int __init loglevel(char *str)

early_param("loglevel", loglevel);

+#ifdef CONFIG_SKC
+__initdata unsigned long initial_skc;
+__initdata unsigned long initial_skc_len;
+
+static int __init save_skc_address(char *str)
+{
+ char *p;
+
+ p = strchr(str, ',');
+ if (!p)
+ return -EINVAL;
+ *p++ = '\0';
+ /* First options should be physical address - int is not enough */
+ if (kstrtoul(str, 0, &initial_skc) < 0)
+ return -EINVAL;
+ if (kstrtoul(p, 0, &initial_skc_len) < 0)
+ return -EINVAL;
+ if (initial_skc_len > SKC_DATA_MAX)
+ return -E2BIG;
+ /* Reserve it for protection */
+ memblock_reserve(initial_skc, initial_skc_len);
+
+ return 0;
+}
+early_param("skc", save_skc_address);
+
+static void __init setup_skc(void)
+{
+ u32 size;
+ char *data, *copy;
+
+ if (!initial_skc)
+ return;
+
+ data = early_memremap(initial_skc, initial_skc_len);
+ size = initial_skc_len + 1;
+
+ copy = memblock_alloc(size, SMP_CACHE_BYTES);
+ if (!copy) {
+ pr_err("Failed to allocate memory for structured kernel cmdline\n");
+ goto end;
+ }
+ memcpy(copy, data, initial_skc_len);
+ copy[size - 1] = '\0';
+
+ skc_init(copy);
+end:
+ early_memunmap(data, initial_skc_len);
+}
+#else
+#define setup_skc() 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)
@@ -596,6 +649,7 @@ asmlinkage __visible void __init start_kernel(void)
setup_arch(&command_line);
mm_init_cpumask(&init_mm);
setup_command_line(command_line);
+ setup_skc();
setup_nr_cpu_ids();
setup_per_cpu_areas();
smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */