Date: Fri, 11 May 2012 14:05:38 -0400 From: Warner Losh <IMP@bsdimp.com> To: "arm@freebsd.org" <arm@freebsd.org> Subject: Changes to locore.S needing review Message-ID: <D33F04CE-139A-46F0-B73F-AFCAC56F74AD@bsdimp.com>
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I'd like to get a review on the locore.S part of the changes that I'm =
making to support booting from a Linux boot loader directly for the =
kernel. My arm assembler knowledge is somewhat weak, so I hope I =
haven't botched anything.
The changes conditionally save r0, r1 and r2 away for the early boot, =
then put them in a structure to pass to board_init(). It also tries to =
clean up the register usage a bit so I can save away these values in =
registers and I don't have to worry about storing values.
Please let me know what you think.
Warner
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Index: arm/locore.S
===================================================================
--- arm/locore.S (revision 235278)
+++ arm/locore.S (working copy)
@@ -37,6 +37,8 @@
#include <machine/asm.h>
#include <machine/armreg.h>
#include <machine/pte.h>
+#include <machine/md_var.h>
+
__FBSDID("$FreeBSD$");
/* What size should this really be ? It is only used by initarm() */
@@ -61,15 +63,26 @@
.globl physaddr
.set physaddr,PHYSADDR
-ENTRY_NP(btext)
-
/*
- * On entry:
+ * On entry for FreeBSD boot ABI:
* r0 - metadata pointer or 0
* r1 - if (r0 == 0) then metadata pointer
+ * initarm gets passed this metadata as arg1 with 0 as arg2.
+ * On entry for Linux boot ABI:
+ * r0 - 0
+ * r1 - machine type (passed as arg2 to initarm)
+ * r2 - Pointer to a tagged list or dtb image (phys addr) (passed as arg1 initarm)
*/
+ENTRY_NP(btext)
ASENTRY_NP(_start)
+#ifdef LINUX_BOOT_ABI
+ /* Maybe we should just always do this and let the boards sort it out */
+ mov r9, r0 /* 0 or boot mode from boot2 */
+ mov r8, r1 /* Save Machine type */
+ mov ip, r2 /* Save meta data */
+ mov fp, r3 /* Save r3 */
+#else
/* Move metadata ptr to r12 (ip) */
mov ip, r0
ldr r0, =0
@@ -77,6 +90,7 @@
bne 1f
mov ip, r1
1:
+#endif
/* Make sure interrupts are disabled. */
mrs r7, cpsr
orr r7, r7, #(I32_bit|F32_bit)
@@ -91,25 +105,25 @@
*/
mrc p15, 0, r2, c1, c0, 0
ands r2, r2, #CPU_CONTROL_MMU_ENABLE
- ldreq r8, =PHYSADDR
- ldrne r8, =LOADERRAMADDR
- cmp r7, r8
+ ldreq r6, =PHYSADDR
+ ldrne r6, =LOADERRAMADDR
+ cmp r7, r6
bls flash_lower
cmp r7, pc
bhi from_ram
b do_copy
flash_lower:
- cmp r8, pc
+ cmp r6, pc
bls from_ram
do_copy:
- ldr r9, =KERNBASE
+ ldr r7, =KERNBASE
adr r1, _start
ldr r0, Lreal_start
ldr r2, Lend
sub r2, r2, r0
- sub r0, r0, r9
- add r0, r0, r8
+ sub r0, r0, r7
+ add r0, r0, r6
mov r4, r0
bl memcpy
ldr r0, Lram_offset
@@ -186,7 +200,19 @@
ldr pc, .Lvirt_done
virt_done:
+#ifdef LINUX_BOOT_ABI
+ mov r0, sp
+ adds sp, sp, #20
+ str r9, [r0] /* Store r0 from boot loader usually 0 */
+ str r8, [r0, #4] /* Store r1 from boot loader machine type */
+ str ip, [r0, #8] /* store r2 from boot loader meta data atag or dtb */
+ str fp, [r0, #12] /* store r3 from boot loader */
+ ld r1, =ARM_FBSDBOOT_MAGIC
+ str r1, [r0, #16]
+#else
mov r0, ip /* Load argument: metadata ptr */
+ mov r1, #0 /* No machine type passed from boot loader */
+#endif
mov fp, #0 /* trace back starts here */
bl _C_LABEL(initarm) /* Off we go */
Index: include/md_var.h
===================================================================
--- include/md_var.h (revision 235107)
+++ include/md_var.h (working copy)
@@ -33,6 +33,7 @@
#ifndef _MACHINE_MD_VAR_H_
#define _MACHINE_MD_VAR_H_
+#ifndef __ASSEMBLER__
extern char sigcode[];
extern int szsigcode;
extern uint32_t *vm_page_dump;
@@ -69,11 +70,22 @@
};
extern enum cpu_class cpu_class;
+struct arm_boot_params {
+ uintptr_t r0;
+ uintptr_t r1;
+ uintptr_t r2;
+ uintptr_t r3;
+ uintptr_t magic;
+};
+
struct dumperinfo;
extern int busdma_swi_pending;
void busdma_swi(void);
void dump_add_page(vm_paddr_t);
void dump_drop_page(vm_paddr_t);
void minidumpsys(struct dumperinfo *);
+#endif
+#define ARM_FBSDBOOT_MAGIC 0x46425344
+
#endif /* !_MACHINE_MD_VAR_H_ */
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