From 0f05da6d577b80eb00f15994c86e4812ae60f1b9 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Wed, 22 Feb 2006 16:20:11 -0800 Subject: [PATCH] [SPARC64]: Fix %tstate ASI handling in start_thread{,32}() Niagara helps us find a ancient bug in the sparc64 port :-) The ASI_* values are plain constant defines, thus signed 32-bit on sparc64. To put shift this into the regs->tstate value we were doing or'ing "(ASI_PNF << 24)" into there. ASI_PNF is 0x82 and shifted left by 24 makes that topmost bit the sign bit in a 32-bit value. This would get sign extended to 64-bits and thus corrupt the top-half of the reg->tstate value. This never caused problems in pre-Niagara cpus because the only thing up there were the condition code values. But Niagara has the global register level field, and this all 1's value is illegal there so Niagara gives an illegal instruction trap due to this bug. I'm pretty sure this bug is about as old as the sparc64 port itself. This also points out that we weren't setting ASI_PNF for 32-bit tasks. We should, so fix that while we're here. Signed-off-by: David S. Miller --- include/asm-sparc64/processor.h | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/include/asm-sparc64/processor.h b/include/asm-sparc64/processor.h index b3889f3f943a..685479fb4364 100644 --- a/include/asm-sparc64/processor.h +++ b/include/asm-sparc64/processor.h @@ -91,7 +91,8 @@ extern unsigned long thread_saved_pc(struct task_struct *); /* Do necessary setup to start up a newly executed thread. */ #define start_thread(regs, pc, sp) \ do { \ - regs->tstate = (regs->tstate & (TSTATE_CWP)) | (TSTATE_INITIAL_MM|TSTATE_IE) | (ASI_PNF << 24); \ + unsigned long __asi = ASI_PNF; \ + regs->tstate = (regs->tstate & (TSTATE_CWP)) | (TSTATE_INITIAL_MM|TSTATE_IE) | (__asi << 24UL); \ regs->tpc = ((pc & (~3)) - 4); \ regs->tnpc = regs->tpc + 4; \ regs->y = 0; \ @@ -128,10 +129,10 @@ do { \ #define start_thread32(regs, pc, sp) \ do { \ + unsigned long __asi = ASI_PNF; \ pc &= 0x00000000ffffffffUL; \ sp &= 0x00000000ffffffffUL; \ -\ - regs->tstate = (regs->tstate & (TSTATE_CWP))|(TSTATE_INITIAL_MM|TSTATE_IE|TSTATE_AM); \ + regs->tstate = (regs->tstate & (TSTATE_CWP))|(TSTATE_INITIAL_MM|TSTATE_IE|TSTATE_AM) | (__asi << 24UL); \ regs->tpc = ((pc & (~3)) - 4); \ regs->tnpc = regs->tpc + 4; \ regs->y = 0; \ -- 2.30.2