186 lines
5.2 KiB
Diff
186 lines
5.2 KiB
Diff
Author: Adrian Panella <ianchi74@outlook.com>
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Date: Fri Jun 10 19:10:15 2016 -0500
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generic: Mangle bootloader's kernel arguments
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The command-line arguments provided by the boot loader will be
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appended to a new device tree property: bootloader-args.
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If there is a property "append-rootblock" in DT under /chosen
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and a root= option in bootloaders command line it will be parsed
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and added to DT bootargs with the form: <append-rootblock>XX.
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Only command line ATAG will be processed, the rest of the ATAGs
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sent by bootloader will be ignored.
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This is usefull in dual boot systems, to get the current root partition
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without afecting the rest of the system.
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Signed-off-by: Adrian Panella <ianchi74@outlook.com>
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--- a/arch/arm/Kconfig
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+++ b/arch/arm/Kconfig
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@@ -1928,6 +1928,17 @@ config ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEN
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The command-line arguments provided by the boot loader will be
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appended to the the device tree bootargs property.
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+config ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE
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+ bool "Append rootblock parsing bootloader's kernel arguments"
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+ help
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+ The command-line arguments provided by the boot loader will be
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+ appended to a new device tree property: bootloader-args.
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+ If there is a property "append-rootblock" in DT under /chosen
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+ and a root= option in bootloaders command line it will be parsed
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+ and added to DT bootargs with the form: <append-rootblock>XX.
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+ Only command line ATAG will be processed, the rest of the ATAGs
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+ sent by bootloader will be ignored.
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+
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endchoice
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config CMDLINE
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--- a/arch/arm/boot/compressed/atags_to_fdt.c
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+++ b/arch/arm/boot/compressed/atags_to_fdt.c
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@@ -3,6 +3,8 @@
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#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND)
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#define do_extend_cmdline 1
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+#elif defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
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+#define do_extend_cmdline 1
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#else
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#define do_extend_cmdline 0
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#endif
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@@ -66,6 +68,59 @@ static uint32_t get_cell_size(const void
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return cell_size;
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}
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+#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
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+
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+static char *append_rootblock(char *dest, const char *str, int len, void *fdt)
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+{
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+ char *ptr, *end;
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+ char *root="root=";
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+ int i, l;
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+ const char *rootblock;
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+
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+ //ARM doesn't have __HAVE_ARCH_STRSTR, so search manually
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+ ptr = str - 1;
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+
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+ do {
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+ //first find an 'r' at the begining or after a space
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+ do {
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+ ptr++;
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+ ptr = strchr(ptr, 'r');
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+ if(!ptr) return dest;
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+
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+ } while (ptr != str && *(ptr-1) != ' ');
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+
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+ //then check for the rest
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+ for(i = 1; i <= 4; i++)
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+ if(*(ptr+i) != *(root+i)) break;
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+
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+ } while (i != 5);
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+
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+ end = strchr(ptr, ' ');
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+ end = end ? (end - 1) : (strchr(ptr, 0) - 1);
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+
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+ //find partition number (assumes format root=/dev/mtdXX | /dev/mtdblockXX | yy:XX )
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+ for( i = 0; end >= ptr && *end >= '0' && *end <= '9'; end--, i++);
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+ ptr = end + 1;
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+
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+ /* if append-rootblock property is set use it to append to command line */
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+ rootblock = getprop(fdt, "/chosen", "append-rootblock", &l);
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+ if(rootblock != NULL) {
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+ if(*dest != ' ') {
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+ *dest = ' ';
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+ dest++;
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+ len++;
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+ }
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+ if (len + l + i <= COMMAND_LINE_SIZE) {
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+ memcpy(dest, rootblock, l);
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+ dest += l - 1;
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+ memcpy(dest, ptr, i);
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+ dest += i;
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+ }
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+ }
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+ return dest;
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+}
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+#endif
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+
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static void merge_fdt_bootargs(void *fdt, const char *fdt_cmdline)
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{
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char cmdline[COMMAND_LINE_SIZE];
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@@ -85,12 +140,21 @@ static void merge_fdt_bootargs(void *fdt
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/* and append the ATAG_CMDLINE */
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if (fdt_cmdline) {
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+
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+#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
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+ //save original bootloader args
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+ //and append ubi.mtd with root partition number to current cmdline
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+ setprop_string(fdt, "/chosen", "bootloader-args", fdt_cmdline);
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+ ptr = append_rootblock(ptr, fdt_cmdline, len, fdt);
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+
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+#else
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len = strlen(fdt_cmdline);
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if (ptr - cmdline + len + 2 < COMMAND_LINE_SIZE) {
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*ptr++ = ' ';
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memcpy(ptr, fdt_cmdline, len);
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ptr += len;
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}
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+#endif
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}
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*ptr = '\0';
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@@ -147,7 +211,9 @@ int atags_to_fdt(void *atag_list, void *
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else
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setprop_string(fdt, "/chosen", "bootargs",
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atag->u.cmdline.cmdline);
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- } else if (atag->hdr.tag == ATAG_MEM) {
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+ }
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+#ifndef CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE
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+ else if (atag->hdr.tag == ATAG_MEM) {
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if (memcount >= sizeof(mem_reg_property)/4)
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continue;
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if (!atag->u.mem.size)
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@@ -186,6 +252,10 @@ int atags_to_fdt(void *atag_list, void *
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setprop(fdt, "/memory", "reg", mem_reg_property,
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4 * memcount * memsize);
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}
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+#else
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+
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+ }
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+#endif
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return fdt_pack(fdt);
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}
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--- a/init/main.c
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+++ b/init/main.c
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@@ -89,6 +89,10 @@
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#include <asm/sections.h>
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#include <asm/cacheflush.h>
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+#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
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+#include <linux/of.h>
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+#endif
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+
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static int kernel_init(void *);
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extern void init_IRQ(void);
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@@ -562,6 +566,18 @@ asmlinkage __visible void __init start_k
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page_alloc_init();
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pr_notice("Kernel command line: %s\n", boot_command_line);
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+
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+#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
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+ //Show bootloader's original command line for reference
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+ if(of_chosen) {
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+ const char *prop = of_get_property(of_chosen, "bootloader-args", NULL);
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+ if(prop)
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+ pr_notice("Bootloader command line (ignored): %s\n", prop);
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+ else
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+ pr_notice("Bootloader command line not present\n");
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+ }
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+#endif
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+
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/* parameters may set static keys */
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jump_label_init();
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parse_early_param();
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