linux/arch/arc/kernel/entry.S, branch v4.5

ARC: [arcompact] Handle bus error from userspace as Interrupt not exception

2015-11-14T07:42:20Z

Bus errors from userspace on ARCompact based cores are handled by core as a high priority L2 interrupt but current code treated it as interrupt Handling an interrupt like exception is certainly not going to go unnoticed. (and it worked so far as we never saw a Bus error from userspace until IPPK guys tested a DDR controller with ECC error detection etc hence needed to explicitly trigger/handle such errors) - So move mem_service exception handler from common code into ARCv2 code. - In ARCompact code, define mem_service as L2 interrupt handler which just drops down to pure kernel mode and goes of to enqueue SIGBUS Reported-by: Nelson Pereira Tested-by: Ana Martins Signed-off-by: Vineet Gupta

ARC: change some branchs to jumps to resolve linkage errors

2015-08-20T13:23:15Z

When kernel's binary becomes large enough (32M and more) errors may occur during the final linkage stage. It happens because the build system uses short relocations for ARC by default. This problem may be easily resolved by passing -mlong-calls option to GCC to use long absolute jumps (j) instead of short relative branchs (b). But there are fragments of pure assembler code exist which use branchs in inappropriate places and cause a linkage error because of relocations overflow. First of these fragments is .fixup insertion in futex.h and unaligned.c. It inserts a code in the separate section (.fixup) with branch instruction. It leads to the linkage error when kernel becomes large. Second of these fragments is calling scheduler's functions (common kernel code) from entry.S of ARC's code. When kernel's binary becomes large it may lead to the linkage error because scheduler may occur far enough from ARC's code in the final binary. Signed-off-by: Yuriy Kolerov Signed-off-by: Vineet Gupta

ARC: entry.S: micro-optimize Trap handler

2015-06-19T12:39:39Z

Elide the need to re-read ECR in Trap handler by ensuring that EXCEPTION_PROLOGUE does that at the very end just before returning to Trap handler ARCv2 EXCEPTION_PROLOGUE already did that, so same for ARcompact and the common trap handler adjusted to use cached ECR Signed-off-by: Vineet Gupta

ARC: entry.S: move some code around for cache locality in return path

2015-06-19T12:39:38Z

Signed-off-by: Vineet Gupta

ARC: entry.S: split into ARCompact ISA specific, common bits

2015-06-19T12:39:38Z

Signed-off-by: Vineet Gupta

ARC: entry.S: Ensure that restore_regs is local to compilation unit

2015-06-19T12:39:37Z

This fixes the possible link/relo errors, since restore_regs will be provided by ISA code, but called from ARC common code. The .L prefix reassures binutils that it will be in same compilation unit. Signed-off-by: Vineet Gupta

ARC: entry.S: comments cleanup

2015-06-19T12:39:37Z

Signed-off-by: Vineet Gupta

ARC: entry.S: Trap handler to use r10 for syscall vs. brkpt decision

2015-06-19T12:39:36Z

Signed-off-by: Vineet Gupta

ARC: entry.S: FAKE_RET_FROM_EXCPN can always use r9

2015-06-19T12:39:36Z

Signed-off-by: Vineet Gupta

ARC: entry.S: confine EXCEPTION_* macros to one file

2015-06-19T12:39:35Z

Signed-off-by: Vineet Gupta