powerpc/boot: Define a routine to enter prom

This patch defines a 'prom' routine similar to 'enter_prom' in the kernel. The difference is in the MSR which is built before entering prom. Big endian order is enforced as in the kernel but 32bit mode is not. It prepares ground for the next patches which will introduce Little endian order. Signed-off-by: Cédric Le Goater <clg@fr.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc/boot: Define a routine to enter prom
This patch defines a 'prom' routine similar to 'enter_prom' in the kernel. The difference is in the MSR which is built before entering prom. Big endian order is enforced as in the kernel but 32bit mode is not. It prepares ground for the next patches which will introduce Little endian order. Signed-off-by: Cédric Le Goater <clg@fr.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cédric Le Goater · Benjamin Herrenschmidt
1 parent 002c39dba3
Showing 2 changed files with 77 additions and 0 deletions Side-by-side Diff
arch/powerpc/boot/crt0.S
arch/powerpc/boot/oflib.c
@@ -126,4 +126,75 @@
  
 	/* Call start */
 	b	start
+
+#ifdef __powerpc64__
+
+#define PROM_FRAME_SIZE 512
+#define SAVE_GPR(n, base)       std     n,8*(n)(base)
+#define REST_GPR(n, base)       ld      n,8*(n)(base)
+#define SAVE_2GPRS(n, base)     SAVE_GPR(n, base); SAVE_GPR(n+1, base)
+#define SAVE_4GPRS(n, base)     SAVE_2GPRS(n, base); SAVE_2GPRS(n+2, base)
+#define SAVE_8GPRS(n, base)     SAVE_4GPRS(n, base); SAVE_4GPRS(n+4, base)
+#define SAVE_10GPRS(n, base)    SAVE_8GPRS(n, base); SAVE_2GPRS(n+8, base)
+#define REST_2GPRS(n, base)     REST_GPR(n, base); REST_GPR(n+1, base)
+#define REST_4GPRS(n, base)     REST_2GPRS(n, base); REST_2GPRS(n+2, base)
+#define REST_8GPRS(n, base)     REST_4GPRS(n, base); REST_4GPRS(n+4, base)
+#define REST_10GPRS(n, base)    REST_8GPRS(n, base); REST_2GPRS(n+8, base)
+
+/* prom handles the jump into and return from firmware.  The prom args pointer
+   is loaded in r3. */
+.globl prom
+prom:
+	mflr	r0
+	std	r0,16(r1)
+	stdu	r1,-PROM_FRAME_SIZE(r1) /* Save SP and create stack space */
+
+	SAVE_GPR(2, r1)
+	SAVE_GPR(13, r1)
+	SAVE_8GPRS(14, r1)
+	SAVE_10GPRS(22, r1)
+	mfcr    r10
+	std     r10,8*32(r1)
+	mfmsr   r10
+	std     r10,8*33(r1)
+
+	/* remove MSR_LE from msr but keep MSR_SF */
+	mfmsr	r10
+	rldicr	r10,r10,0,62
+	mtsrr1	r10
+
+	/* Load FW address, set LR to label 1, and jump to FW */
+	bl	0f
+0:	mflr	r10
+	addi	r11,r10,(1f-0b)
+	mtlr	r11
+
+	ld	r10,(p_prom-0b)(r10)
+	mtsrr0	r10
+
+	rfid
+
+1:	/* Return from OF */
+
+	/* Restore registers and return. */
+	rldicl  r1,r1,0,32
+
+	/* Restore the MSR (back to 64 bits) */
+	ld      r10,8*(33)(r1)
+	mtmsr	r10
+	isync
+
+	/* Restore other registers */
+	REST_GPR(2, r1)
+	REST_GPR(13, r1)
+	REST_8GPRS(14, r1)
+	REST_10GPRS(22, r1)
+	ld      r10,8*32(r1)
+	mtcr	r10
+
+	addi    r1,r1,PROM_FRAME_SIZE
+	ld      r0,16(r1)
+	mtlr    r0
+	blr
+#endif
@@ -27,11 +27,17 @@
 	__be32 args[10];	/* Input/output arguments. */
 };
  
+#ifdef __powerpc64__
+extern int prom(void *);
+#else
 static int (*prom) (void *);
+#endif
  
 void of_init(void *promptr)
 {
+#ifndef __powerpc64__
 	prom = (int (*)(void *))promptr;
+#endif
 }
  
 #define ADDR(x)		(u32)(unsigned long)(x)
...	...	@@ -126,4 +126,75 @@
126	126
127	127	/* Call start */
128	128	b start
	129	+
	130	+#ifdef __powerpc64__
	131	+
	132	+#define PROM_FRAME_SIZE 512
	133	+#define SAVE_GPR(n, base) std n,8*(n)(base)
	134	+#define REST_GPR(n, base) ld n,8*(n)(base)
	135	+#define SAVE_2GPRS(n, base) SAVE_GPR(n, base); SAVE_GPR(n+1, base)
	136	+#define SAVE_4GPRS(n, base) SAVE_2GPRS(n, base); SAVE_2GPRS(n+2, base)
	137	+#define SAVE_8GPRS(n, base) SAVE_4GPRS(n, base); SAVE_4GPRS(n+4, base)
	138	+#define SAVE_10GPRS(n, base) SAVE_8GPRS(n, base); SAVE_2GPRS(n+8, base)
	139	+#define REST_2GPRS(n, base) REST_GPR(n, base); REST_GPR(n+1, base)
	140	+#define REST_4GPRS(n, base) REST_2GPRS(n, base); REST_2GPRS(n+2, base)
	141	+#define REST_8GPRS(n, base) REST_4GPRS(n, base); REST_4GPRS(n+4, base)
	142	+#define REST_10GPRS(n, base) REST_8GPRS(n, base); REST_2GPRS(n+8, base)
	143	+
	144	+/* prom handles the jump into and return from firmware. The prom args pointer
	145	+ is loaded in r3. */
	146	+.globl prom
	147	+prom:
	148	+ mflr r0
	149	+ std r0,16(r1)
	150	+ stdu r1,-PROM_FRAME_SIZE(r1) /* Save SP and create stack space */
	151	+
	152	+ SAVE_GPR(2, r1)
	153	+ SAVE_GPR(13, r1)
	154	+ SAVE_8GPRS(14, r1)
	155	+ SAVE_10GPRS(22, r1)
	156	+ mfcr r10
	157	+ std r10,8*32(r1)
	158	+ mfmsr r10
	159	+ std r10,8*33(r1)
	160	+
	161	+ /* remove MSR_LE from msr but keep MSR_SF */
	162	+ mfmsr r10
	163	+ rldicr r10,r10,0,62
	164	+ mtsrr1 r10
	165	+
	166	+ /* Load FW address, set LR to label 1, and jump to FW */
	167	+ bl 0f
	168	+0: mflr r10
	169	+ addi r11,r10,(1f-0b)
	170	+ mtlr r11
	171	+
	172	+ ld r10,(p_prom-0b)(r10)
	173	+ mtsrr0 r10
	174	+
	175	+ rfid
	176	+
	177	+1: /* Return from OF */
	178	+
	179	+ /* Restore registers and return. */
	180	+ rldicl r1,r1,0,32
	181	+
	182	+ /* Restore the MSR (back to 64 bits) */
	183	+ ld r10,8*(33)(r1)
	184	+ mtmsr r10
	185	+ isync
	186	+
	187	+ /* Restore other registers */
	188	+ REST_GPR(2, r1)
	189	+ REST_GPR(13, r1)
	190	+ REST_8GPRS(14, r1)
	191	+ REST_10GPRS(22, r1)
	192	+ ld r10,8*32(r1)
	193	+ mtcr r10
	194	+
	195	+ addi r1,r1,PROM_FRAME_SIZE
	196	+ ld r0,16(r1)
	197	+ mtlr r0
	198	+ blr
	199	+#endif
...	...	@@ -27,11 +27,17 @@
27	27	__be32 args[10]; /* Input/output arguments. */
28	28	};
29	29
	30	+#ifdef __powerpc64__
	31	+extern int prom(void *);
	32	+#else
30	33	static int (prom) (void );
	34	+#endif
31	35
32	36	void of_init(void *promptr)
33	37	{
	38	+#ifndef __powerpc64__
34	39	prom = (int ()(void ))promptr;
	40	+#endif
35	41	}
36	42
37	43	#define ADDR(x) (u32)(unsigned long)(x)