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| author |   Cédric Le Goater <clg@fr.ibm.com> | 2014-04-24 09:23:36 +0200 |
|---|---|---|
| committer |   Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2014-04-28 17:36:08 +1000 |
| commit | 93d3921042988317e94b1bcc2e19844efe0b7356 (patch) | |
| tree | 66cf4989366fe198c1394d24f1f912e39ef0df31 /arch/powerpc/boot/crt0.S | |
| parent | powerpc/boot: Add little endian support to elf utils (diff) | |
| download | linux-dev-93d3921042988317e94b1bcc2e19844efe0b7356.tar.xz linux-dev-93d3921042988317e94b1bcc2e19844efe0b7356.zip | |
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>
Diffstat (limited to 'arch/powerpc/boot/crt0.S')
| -rw-r--r-- | arch/powerpc/boot/crt0.S | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/arch/powerpc/boot/crt0.S b/arch/powerpc/boot/crt0.S index 0f7428a37efb..dbd99d064828 100644 --- a/arch/powerpc/boot/crt0.S +++ b/arch/powerpc/boot/crt0.S @@ -126,3 +126,74 @@ RELACOUNT = 0x6ffffff9 /* 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 |