[PATCH] Editable kernel command-line in zImage binary.
mostrows at watson.ibm.com
mostrows at watson.ibm.com
Fri Jun 9 23:06:12 EST 2006
zImage will set /chosen/bootargs (if it is otherwise empty) with the
contents of a buffer in the section "__builtin_cmdline". This permits
tools to edit zImage binaries to set the command-line eventually
processed by vmlinux.
--
Signed-off-by: Michal Ostrowski <mostrows at watson.ibm.com>
---
arch/powerpc/boot/main.c | 27 +++++++++++++++++++++++++++
arch/powerpc/boot/prom.h | 7 +++++++
2 files changed, 34 insertions(+), 0 deletions(-)
40bea6ace95796a1575437d6dfdbef671012ffc1
diff --git a/arch/powerpc/boot/main.c b/arch/powerpc/boot/main.c
index 816446f..c65a7ba 100644
--- a/arch/powerpc/boot/main.c
+++ b/arch/powerpc/boot/main.c
@@ -33,6 +33,14 @@ extern char _vmlinux_end[];
extern char _initrd_start[];
extern char _initrd_end[];
+/* A buffer that may be edited by tools operating on a zImage binary so as to
+ * edit the command line passed to vmlinux (by setting /chosen/bootargs).
+ * The buffer is put in it's own section so that tools may locate it easier.
+ */
+static char builtin_cmdline[512]
+ __attribute__((section("__builtin_cmdline")));
+
+
struct addr_range {
unsigned long addr;
unsigned long size;
@@ -204,6 +212,23 @@ static int is_elf32(void *hdr)
return 1;
}
+void export_cmdline(void* chosen_handle)
+{
+ int len;
+ char cmdline[2] = { 0, 0 };
+
+ if (builtin_cmdline[0] == 0)
+ return;
+
+ len = getprop(chosen_handle, "bootargs", cmdline, sizeof(cmdline));
+ if (len > 0 && cmdline[0] != 0)
+ return;
+
+ setprop(chosen_handle, "bootargs", builtin_cmdline,
+ strlen(builtin_cmdline) + 1);
+}
+
+
void start(unsigned long a1, unsigned long a2, void *promptr, void *sp)
{
int len;
@@ -289,6 +314,8 @@ void start(unsigned long a1, unsigned lo
memmove((void *)vmlinux.addr,(void *)vmlinuz.addr,vmlinuz.size);
}
+ export_cmdline(chosen_handle);
+
/* Skip over the ELF header */
#ifdef DEBUG
printf("... skipping 0x%lx bytes of ELF header\n\r",
diff --git a/arch/powerpc/boot/prom.h b/arch/powerpc/boot/prom.h
index 3e2ddd4..a57b184 100644
--- a/arch/powerpc/boot/prom.h
+++ b/arch/powerpc/boot/prom.h
@@ -31,4 +31,11 @@ static inline int getprop(void *phandle,
return call_prom("getprop", 4, 1, phandle, name, buf, buflen);
}
+
+static inline int setprop(void *phandle, const char *name,
+ void *buf, int buflen)
+{
+ return call_prom("setprop", 4, 1, phandle, name, buf, buflen);
+}
+
#endif /* _PPC_BOOT_PROM_H_ */
--
1.1.4.g0b63-dirty
More information about the Linuxppc-dev
mailing list