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linux-user/sparc: Fix errors in target_ucontext structures

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The various structs that make up the SPARC target_ucontext had some
errors:
 * target structures must not include fields which are host pointers,
   which might be the wrong size.  These should be abi_ulong instead
 * because we don't have the 'long double' part of the mcfpu_fregs
   union in our version of the target_mc_fpu struct, we need to
   manually force it to be 16-aligned

In particular, the lack of 16-alignment caused sparc64_get_context()
and sparc64_set_context() to read and write all the registers at the
wrong offset, which triggered a guest glibc stack check in
siglongjmp:
  *** longjmp causes uninitialized stack frame ***: terminated
when trying to run bash.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201105212314.9628-2-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
This commit is contained in:
Peter Maydell 2020-11-05 21:23:12 +00:00 committed by Laurent Vivier
parent 43afbbd9fe
commit b8ae597f0e
1 changed files with 9 additions and 4 deletions
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13
linux-user/sparc/signal.c
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@ -349,10 +349,15 @@ typedef abi_ulong target_mc_greg_t;
typedef target_mc_greg_t target_mc_gregset_t[SPARC_MC_NGREG];
struct target_mc_fq {
abi_ulong *mcfq_addr;
abi_ulong mcfq_addr;
uint32_t mcfq_insn;
};
/*
* Note the manual 16-alignment; the kernel gets this because it
* includes a "long double qregs[16]" in the mcpu_fregs union,
* which we can't do.
*/
struct target_mc_fpu {
union {
uint32_t sregs[32];
@ -362,11 +367,11 @@ struct target_mc_fpu {
abi_ulong mcfpu_fsr;
abi_ulong mcfpu_fprs;
abi_ulong mcfpu_gsr;
struct target_mc_fq *mcfpu_fq;
abi_ulong mcfpu_fq;
unsigned char mcfpu_qcnt;
unsigned char mcfpu_qentsz;
unsigned char mcfpu_enab;
};
} __attribute__((aligned(16)));
typedef struct target_mc_fpu target_mc_fpu_t;
typedef struct {
@ -377,7 +382,7 @@ typedef struct {
} target_mcontext_t;
struct target_ucontext {
struct target_ucontext *tuc_link;
abi_ulong tuc_link;
abi_ulong tuc_flags;
target_sigset_t tuc_sigmask;
target_mcontext_t tuc_mcontext;