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2023-10-18linux-user/sh4: Fix crashes on signal deliveryMikulas Patocka
sh4 uses gUSA (general UserSpace Atomicity) to provide atomicity on CPUs that don't have atomic instructions. A gUSA region that adds 1 to an atomic variable stored in @R2 looks like this: 4004b6: 03 c7 mova 4004c4 <gusa+0x10>,r0 4004b8: f3 61 mov r15,r1 4004ba: 09 00 nop 4004bc: fa ef mov #-6,r15 4004be: 22 63 mov.l @r2,r3 4004c0: 01 73 add #1,r3 4004c2: 32 22 mov.l r3,@r2 4004c4: 13 6f mov r1,r15 R0 contains a pointer to the end of the gUSA region R1 contains the saved stack pointer R15 contains negative length of the gUSA region When this region is interrupted by a signal, the kernel detects if R15 >= -128U. If yes, the kernel rolls back PC to the beginning of the region and restores SP by copying R1 to R15. The problem happens if we are interrupted by a signal at address 4004c4. R15 still holds the value -6, but the atomic value was already written by an instruction at address 4004c2. In this situation we can't undo the gUSA. The function unwind_gusa does nothing, the signal handler attempts to push a signal frame to the address -6 and crashes. This patch fixes it, so that if we are interrupted at the last instruction in a gUSA region, we copy R1 to R15 to restore the correct stack pointer and avoid crashing. There's another bug: if we are interrupted in a delay slot, we save the address of the instruction in the delay slot. We must save the address of the previous instruction. Cc: qemu-stable@nongnu.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Yoshinori Sato <ysato@users.sourcefoege.jp> Message-Id: <b16389f7-6c62-70b7-59b3-87533c0bcc@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2022-10-04target/sh4: Fix TB_FLAG_UNALIGNRichard Henderson
The value previously chosen overlaps GUSA_MASK. Rename all DELAY_SLOT_* and GUSA_* defines to emphasize that they are included in TB_FLAGs. Add aliases for the FPSCR and SR bits that are included in TB_FLAGS, so that we don't accidentally reassign those bits. Fixes: 4da06fb3062 ("target/sh4: Implement prctl_unalign_sigbus") Resolves: https://gitlab.com/qemu-project/qemu/-/issues/856 Reviewed-by: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-12-19linux-user: Rename TARGET_QEMU_ESIGRETURN to QEMU_ESIGRETURNRichard Henderson
This value is fully internal to qemu, and so is not a TARGET define. Reviewed-by: Warner Losh <imp@bsdimp.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-10-01linux-user/sh4: Implement setup_sigtrampRichard Henderson
Create and record the two signal trampolines. Use them when the guest does not use SA_RESTORER. Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20210929130553.121567-23-richard.henderson@linaro.org> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2021-09-13linux-user: Split linux-user internals out of qemu.hPeter Maydell
qemu.h is included in various non-linux-user files (which mostly want the TaskState struct and the functions for doing usermode access to guest addresses like lock_user(), unlock_user(), get_user*(), etc). Split out the parts that are only used in linux-user itself into a new user-internals.h. This leaves qemu.h with basically three things: * the definition of the TaskState struct * the user-access functions and macros * do_brk() all of which are needed by code outside linux-user that includes qemu.h. The addition of all the extra #include lines was done with sed -i '/include.*qemu\.h/a #include "user-internals.h"' $(git grep -l 'include.*qemu\.h' linux-user) (and then undoing the change to fpa11.h). Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20210908154405.15417-8-peter.maydell@linaro.org> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2021-05-15linux-user: Pass CPUArchState to target_restore_altstackRichard Henderson
In most cases we were already passing get_sp_from_cpustate directly to the function. In other cases, we were passing a local variable which already contained the same value. In the rest of the cases, we were passing the stack pointer out of env directly. Reviewed by: Warner Losh <imp@bsdimp.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20210426025334.1168495-5-richard.henderson@linaro.org> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2021-05-15linux-user: Use target_restore_altstack in all sigreturnRichard Henderson
Note that target_restore_altstack uses the host memory pointer that we have already verified, so TARGET_EFAULT is not a possible return value. Note that using -EFAULT was a bug. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20210426025334.1168495-3-richard.henderson@linaro.org> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2021-03-06accel/tcg: Precompute curr_cflags into cpu->tcg_cflagsRichard Henderson
The primary motivation is to remove a dozen insns along the fast-path in tb_lookup. As a byproduct, this allows us to completely remove parallel_cpus. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-11-12linux-user: Remove dead error-checking codePeter Maydell
Remove some dead code spotted by Coverity (CID 1009855, 1390854, 1390847). The underlying cause in all these cases is the same: QEMU's put_user operations can't result in errors, but the kernel's equivalent does. So when code was copied from the kernel signal-frame-setup/teardown code, checks on error flags that were needed in the kernel became dead code for us. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Message-Id: <20181019161715.12122-1-peter.maydell@linaro.org> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2018-06-04linux-user: move get_sp_from_cpustate() to target_cpu.hLaurent Vivier
Remove useless includes Fix HPPA include guard. Signed-off-by: Laurent Vivier <laurent@vivier.eu> Acked-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20180529194207.31503-9-laurent@vivier.eu>
2018-05-03linux-user: introduce target_sigsp() and target_save_altstack()Laurent Vivier
Signed-off-by: Laurent Vivier <laurent@vivier.eu> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20180411192347.30228-1-laurent@vivier.eu>
2018-04-30linux-user: move sh4 signal.c parts to sh4 directoryLaurent Vivier
No code change, only move code from signal.c to sh4/signal.c, except adding includes and exporting setup_frame() and setup_rt_frame(). Signed-off-by: Laurent Vivier <laurent@vivier.eu> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20180424192635.6027-5-laurent@vivier.eu>
2018-04-30linux-user: create a dummy per arch signal.cLaurent Vivier
Create a signal-common.h for future use by these new files and use it in the existing signal.c Signed-off-by: Laurent Vivier <laurent@vivier.eu> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20180424192635.6027-2-laurent@vivier.eu>
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