Author: nwhitehorn
Date: Fri Dec 29 20:30:10 2017
New Revision: 327358
URL: https://svnweb.freebsd.org/changeset/base/327358
Log:
Add support for 64-bit PowerPC kernels to be directly loaded by kexec, which
is used as the bootloader on a number of PPC64 platforms. This involves the
following pieces:
- Making the first instruction a valid kernel entry point, since kexec
ignores the ELF entry value. This requires a separate section and linker
magic to prevent the linker from filling the beginning of the section
with stubs.
- Adding an entry point at 0x60 past the first instruction for systems
lacking firmware CPU shutdown support (notably PS3).
- Linker script changes to support the above.
MFC after: 1 month
Modified:
head/sys/conf/ldscript.powerpc64
head/sys/powerpc/aim/locore64.S
head/sys/powerpc/include/vmparam.h
Modified: head/sys/conf/ldscript.powerpc64
==============================================================================
--- head/sys/conf/ldscript.powerpc64 Fri Dec 29 20:25:15 2017
(r327357)
+++ head/sys/conf/ldscript.powerpc64 Fri Dec 29 20:30:10 2017
(r327358)
@@ -8,8 +8,12 @@ SEARCH_DIR(/usr/lib);
PROVIDE (__stack = 0);
SECTIONS
{
- /* Read-only sections, merged into text segment: */
+ /* Low-address wrapper for bootloaders (kexec/kboot) that can't parse ELF */
+ . = kernbase - 0x100;
+ .kboot : { *(.text.kboot) }
+
+ /* Read-only sections, merged into text segment: */
. = kernbase;
PROVIDE (begin = .);
@@ -27,6 +31,9 @@ SECTIONS
/* Do not emit PT_INTERP section, which confuses some loaders (kexec-lite) */
.interpX : { *(.interp) } : NONE
/DISCARD/ : { *(.interp) }
+
+ /* Also delete notes */
+ /DISCARD/ : { *(.note.*) }
.hash : { *(.hash) }
.dynsym : { *(.dynsym) }
Modified: head/sys/powerpc/aim/locore64.S
==============================================================================
--- head/sys/powerpc/aim/locore64.S Fri Dec 29 20:25:15 2017
(r327357)
+++ head/sys/powerpc/aim/locore64.S Fri Dec 29 20:30:10 2017
(r327358)
@@ -61,6 +61,47 @@ GLOBAL(tmpstk)
TOC_ENTRY(tmpstk)
+/*
+ * Entry point for bootloaders that do not fully implement ELF and start
+ * at the beginning of the image (kexec, notably). In its own section so
+ * that it ends up before any linker-generated call stubs and actually at
+ * the beginning of the image. kexec on some systems also enters at
+ * (start of image) + 0x60, so put a spin loop there.
+ */
+ .section ".text.kboot", "x", @progbits
+kbootentry:
+ b __start
+. = kbootentry + 0x40 /* Magic address used in platform layer */
+ .global smp_spin_sem
+ap_kexec_spin_sem:
+ .long -1
+. = kbootentry + 0x60 /* Entry point for kexec APs */
+ap_kexec_start: /* At 0x60 past start, copied to 0x60 by kexec
*/
+ /* r3 set to CPU ID by kexec */
+
+ /* Invalidate icache for low-memory copy and jump there */
+ li %r0,0x80
+ dcbst 0,%r0
+ sync
+ icbi 0,%r0
+ isync
+ ba 0x78 /* Absolute branch to next inst */
+
+1: or 31,31,31 /* yield */
+ sync
+ lwz %r1,0x40(0) /* Spin on ap_kexec_spin_sem */
+ cmpw %r1,%r3 /* Until it equals our CPU ID */
+ bne 1b
+
+ /* Released */
+ or 2,2,2 /* unyield */
+ ba EXC_RST
+
+
+/*
+ * Now start the real text section
+ */
+
.text
.globl btext
btext:
Modified: head/sys/powerpc/include/vmparam.h
==============================================================================
--- head/sys/powerpc/include/vmparam.h Fri Dec 29 20:25:15 2017
(r327357)
+++ head/sys/powerpc/include/vmparam.h Fri Dec 29 20:30:10 2017
(r327358)
@@ -108,7 +108,7 @@
#endif
#ifdef AIM
-#define KERNBASE 0x00100000UL /* start of kernel
virtual */
+#define KERNBASE 0x00100100UL /* start of kernel
virtual */
#ifndef __powerpc64__
#define VM_MIN_KERNEL_ADDRESS ((vm_offset_t)KERNEL_SR << ADDR_SR_SHFT)
_______________________________________________
svn-src-all@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
