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D23057: [PowerPC] Fix offset calculations in bridge mode

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In rS354701, I replaced text relocations with offsets from &generictrap.

Unfortunately, the magic variable I was using doesn't actually mean the
address of &generictrap, in bridge mode it actually means &generictrap64.

So, for bridge mode to work, it is necessary to differentiate between
"where do we need to branch to to handle a trap" and "where is &generictrap
for purposes of doing relative math".

Introduce a new TRAP_ENTRY and use it instead of TRAP_GENTRAP for doing
actual calls to the generic trap handler.

Reported by:	Mark Millard <marklmi@yahoo.com>
Reviewed by:	jhibbits
Sponsored by:	Tag1 Consulting, Inc.
Differential Revision:	https://reviews.freebsd.org/D23057
This commit is contained in:
Brandon Bergren 2020-01-18 04:12:41 +00:00
parent 151e04b3fe
commit ee628685e8
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=356862
4 changed files with 14 additions and 11 deletions
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8
sys/powerpc/aim/aim_machdep.c
View File

@ -388,16 +388,18 @@ aim_cpu_init(vm_offset_t toc)
bcopy(&dsitrap, (void *)(EXC_DSI + trap_offset), (size_t)&dsiend -
(size_t)&dsitrap);
/* Set address of generictrap for self-reloc calculations */
*((void **)TRAP_GENTRAP) = &generictrap;
#ifdef __powerpc64__
/* Set TOC base so that the interrupt code can get at it */
*((void **)TRAP_GENTRAP) = &generictrap;
*((void **)TRAP_ENTRY) = &generictrap;
*((register_t *)TRAP_TOCBASE) = toc;
#else
/* Set branch address for trap code */
if (cpu_features & PPC_FEATURE_64)
*((void **)TRAP_GENTRAP) = &generictrap64;
*((void **)TRAP_ENTRY) = &generictrap64;
else
*((void **)TRAP_GENTRAP) = &generictrap;
*((void **)TRAP_ENTRY) = &generictrap;
*((void **)TRAP_TOCBASE) = _GLOBAL_OFFSET_TABLE_;
/* G2-specific TLB miss helper handlers */

4
sys/powerpc/aim/trap_subr32.S
View File

@ -348,7 +348,7 @@ CNAME(trapcode):
mtsprg1 %r1 /* save SP */
mflr %r1 /* Save the old LR in r1 */
mtsprg2 %r1 /* And then in SPRG2 */
lwz %r1, TRAP_GENTRAP(0) /* Get branch address */
lwz %r1, TRAP_ENTRY(0) /* Get branch address */
mtlr %r1
li %r1, 0xe0 /* How to get the vector from LR */
blrl /* LR & (0xff00 | r1) is exception # */
@ -908,7 +908,7 @@ CNAME(dblow):
mflr %r1 /* save LR */
mtsprg2 %r1 /* And then in SPRG2 */
lwz %r1, TRAP_GENTRAP(0) /* Get branch address */
lwz %r1, TRAP_ENTRY(0) /* Get branch address */
mtlr %r1
li %r1, 0 /* How to get the vector from LR */
blrl /* LR & (0xff00 | r1) is exception # */

8
sys/powerpc/aim/trap_subr64.S
View File

@ -318,7 +318,7 @@ CNAME(rstcode):
* It is software reset when 46:47 = 0b00
*/
/* 0x00 */
ld %r2,TRAP_GENTRAP(0) /* Real-mode &generictrap */
ld %r2,TRAP_ENTRY(0) /* Real-mode &generictrap */
mfsrr1 %r9 /* Load SRR1 into r9 */
andis. %r9,%r9,0x3 /* Logic AND with 46:47 bits */
@ -446,7 +446,7 @@ CNAME(trapcode):
mtsprg1 %r1 /* save SP */
mflr %r1 /* Save the old LR in r1 */
mtsprg2 %r1 /* And then in SPRG2 */
ld %r1,TRAP_GENTRAP(0)
ld %r1,TRAP_ENTRY(0)
mtlr %r1
li %r1, 0xe0 /* How to get the vector from LR */
blrl /* Branch to generictrap */
@ -493,7 +493,7 @@ CNAME(slbtrap):
mflr %r1
/* 0x30 */
mtsprg2 %r1 /* save LR in SPRG2 */
ld %r1,TRAP_GENTRAP(0) /* real-mode &generictrap */
ld %r1,TRAP_ENTRY(0) /* real-mode &generictrap */
mtlr %r1
li %r1, 0x80 /* How to get the vector from LR */
/* 0x40 */
@ -955,7 +955,7 @@ CNAME(dblow):
mflr %r1 /* save LR */
mtsprg2 %r1 /* And then in SPRG2 */
ld %r1, TRAP_GENTRAP(0) /* Get branch address */
ld %r1, TRAP_ENTRY(0) /* Get branch address */
mtlr %r1
li %r1, 0 /* How to get the vector from LR */
blrl /* Branch to generictrap */

5
sys/powerpc/include/trap.h
View File

@ -147,8 +147,9 @@
#define EXC_DTRACE 0x7ffff808
/* Magic pointer to store TOC base and other info for trap handlers on ppc64 */
#define TRAP_GENTRAP 0x1f0
#define TRAP_TOCBASE 0x1f8
#define TRAP_ENTRY 0x1e8
#define TRAP_GENTRAP 0x1f0
#define TRAP_TOCBASE 0x1f8
#ifndef LOCORE
struct trapframe;