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Commit 30d8caf7 authored by mostrows@watson.ibm.com's avatar mostrows@watson.ibm.com Committed by Paul Mackerras
Browse files

[POWERPC] Editable kernel command-line in zImage binary. 



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: default avatarMichal Ostrowski <mostrows@watson.ibm.com>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 204face4

arch/powerpc/boot/main.c

+27 −0
Original line number Diff line number Diff line
@@ -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 long a2, void *promptr, void *sp) 
		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",

arch/powerpc/boot/prom.h

+7 −0
Original line number Diff line number Diff line
@@ -31,4 +31,11 @@ static inline int getprop(void *phandle, const char *name, 
	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_ */