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Subject[RFC PATCH 1/2] Revert "csky: Fixup CONFIG_DEBUG_RSEQ"
Date
This reverts commit f36e0aab6f1f78d770ce859df3f07a9c5763ce5f.

The csky rseq support has been merged without ever notifying the rseq
maintainers, and without any of the required asssembler glue in the rseq
selftests, which means it is entirely untested.

It is also derived from a non-upstream riscv patch which has known bugs.

The assembly part of this revert should be carefully reviewed by the
architecture maintainer because it touches code which has changed since
the merge of the reverted patch.

The rseq selftests assembly glue should be introduced at the same time
as the architecture rseq support. Without the presence of any test, I
recommend reverting rseq support from csky for now.

Link: https://lore.kernel.org/lkml/1257037909.25426.1626705790861.JavaMail.zimbra@efficios.com/
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-csky@vger.kernel.org
---
arch/csky/kernel/entry.S | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/arch/csky/kernel/entry.S b/arch/csky/kernel/entry.S
index 00e3c8ebf9b8..d89afe3b24cc 100644
--- a/arch/csky/kernel/entry.S
+++ b/arch/csky/kernel/entry.S
@@ -50,11 +50,15 @@ ENTRY(csky_systemcall)
SAVE_ALL TRAP0_SIZE
zero_fp
context_tracking
+#ifdef CONFIG_RSEQ_DEBUG
+ mov a0, sp
+ jbsr rseq_syscall
+#endif
psrset ee, ie

lrw r9, __NR_syscalls
cmphs syscallid, r9 /* Check nr of syscall */
- bt 1f
+ bt ret_from_exception

lrw r9, sys_call_table
ixw r9, syscallid
@@ -80,11 +84,6 @@ ENTRY(csky_systemcall)
jsr syscallid
#endif
stw a0, (sp, LSAVE_A0) /* Save return value */
-1:
-#ifdef CONFIG_DEBUG_RSEQ
- mov a0, sp
- jbsr rseq_syscall
-#endif
jmpi ret_from_exception

csky_syscall_trace:
@@ -113,10 +112,6 @@ csky_syscall_trace:
stw a0, (sp, LSAVE_A0) /* Save return value */

1:
-#ifdef CONFIG_DEBUG_RSEQ
- mov a0, sp
- jbsr rseq_syscall
-#endif
mov a0, sp /* right now, sp --> pt_regs */
jbsr syscall_trace_exit
br ret_from_exception
--
2.20.1
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