From b61df2294f662540786f2558f691eba7447ff5ba Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Wed, 23 Sep 2015 18:33:49 +0000 Subject: [PATCH] fix signal return for sh/fdpic the restorer function pointer provided in the kernel sigaction structure is interpreted by the kernel as a raw code address, not a function descriptor. this commit moves the declarations of the __restore and __restore_rt symbols to ksigaction.h so that arch versions of the file can override them, and introduces a version for sh which declares them as objects rather than functions. an alternate solution would have been defining SA_RESTORER to 0 so that the functions are not used, but this both requires executable stack (since the sh kernel does not have a vdso page with permanent restorer functions) and crashes on qemu user-level emulation. --- arch/mips/ksigaction.h | 2 ++ arch/sh/ksigaction.h | 8 ++++++++ src/internal/ksigaction.h | 2 ++ src/signal/sh/restore.s | 2 -- src/signal/sigaction.c | 2 -- 5 files changed, 12 insertions(+), 4 deletions(-) create mode 100644 arch/sh/ksigaction.h diff --git a/arch/mips/ksigaction.h b/arch/mips/ksigaction.h index 6d731646..3127f7c0 100644 --- a/arch/mips/ksigaction.h +++ b/arch/mips/ksigaction.h @@ -7,3 +7,5 @@ struct k_sigaction { * mips-specific preprocessor conditionals in sigaction.c. */ void (*restorer)(); }; + +void __restore(), __restore_rt(); diff --git a/arch/sh/ksigaction.h b/arch/sh/ksigaction.h new file mode 100644 index 00000000..0c652bea --- /dev/null +++ b/arch/sh/ksigaction.h @@ -0,0 +1,8 @@ +struct k_sigaction { + void (*handler)(int); + unsigned long flags; + void *restorer; + unsigned mask[2]; +}; + +extern unsigned char __restore[], __restore_rt[]; diff --git a/src/internal/ksigaction.h b/src/internal/ksigaction.h index 2eacabf1..1d8d9646 100644 --- a/src/internal/ksigaction.h +++ b/src/internal/ksigaction.h @@ -7,3 +7,5 @@ struct k_sigaction { void (*restorer)(void); unsigned mask[2]; }; + +void __restore(), __restore_rt(); diff --git a/src/signal/sh/restore.s b/src/signal/sh/restore.s index eaedcdfb..d5df8e14 100644 --- a/src/signal/sh/restore.s +++ b/src/signal/sh/restore.s @@ -1,5 +1,4 @@ .global __restore -.type __restore, @function __restore: mov #119, r3 !__NR_sigreturn trapa #31 @@ -11,7 +10,6 @@ __restore: or r0, r0 .global __restore_rt -.type __restore_rt, @function __restore_rt: mov #100, r3 !__NR_rt_sigreturn add #73, r3 diff --git a/src/signal/sigaction.c b/src/signal/sigaction.c index d5f47741..ab23a6f2 100644 --- a/src/signal/sigaction.c +++ b/src/signal/sigaction.c @@ -6,8 +6,6 @@ #include "libc.h" #include "ksigaction.h" -void __restore(), __restore_rt(); - static int unmask_done; static unsigned long handler_set[_NSIG/(8*sizeof(long))]; -- 2.25.1