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objtool: Handle frame pointer related instructions mainline inclusion from mainline-v6.12-rc1 commit da5b2ad1c2f18834cb1ce429e2e5a5cf5cbdf21b category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IB3IRE Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=da5b2ad1c2f18834cb1ce429e2e5a5cf5cbdf21b --------------------------------------------------------------------------- After commit a0f7085f6a63 ("LoongArch: Add RANDOMIZE_KSTACK_OFFSET support"), there are three new instructions "addi.d $fp, $sp, 32", "sub.d $sp, $sp, $t0" and "addi.d $sp, $fp, -32" for the secondary stack in do_syscall(), then there is a objtool warning "return with modified stack frame" and no handle_syscall() which is the previous frame of do_syscall() in the call trace when executing the command "echo l > /proc/sysrq-trigger". objdump shows something like this: 0000000000000000 <do_syscall>: 0: 02ff8063 addi.d $sp, $sp, -32 4: 29c04076 st.d $fp, $sp, 16 8: 29c02077 st.d $s0, $sp, 8 c: 29c06061 st.d $ra, $sp, 24 10: 02c08076 addi.d $fp, $sp, 32 ... 74: 0011b063 sub.d $sp, $sp, $t0 ... a8: 4c000181 jirl $ra, $t0, 0 ... dc: 02ff82c3 addi.d $sp, $fp, -32 e0: 28c06061 ld.d $ra, $sp, 24 e4: 28c04076 ld.d $fp, $sp, 16 e8: 28c02077 ld.d $s0, $sp, 8 ec: 02c08063 addi.d $sp, $sp, 32 f0: 4c000020 jirl $zero, $ra, 0 The instruction "sub.d $sp, $sp, $t0" changes the stack bottom and the new stack size is a random value, in order to find the return address of do_syscall() which is stored in the original stack frame after executing "jirl $ra, $t0, 0", it should use fp which points to the original stack top. At the beginning, the thought is tended to decode the secondary stack instruction "sub.d $sp, $sp, $t0" and set it as a label, then check this label for the two frame pointer instructions to change the cfa base and cfa offset during the period of secondary stack in update_cfi_state(). This is valid for GCC but invalid for Clang due to there are different secondary stack instructions for ClangBuiltLinux on LoongArch, something like this: 0000000000000000 <do_syscall>: ... 88: 00119064 sub.d $a0, $sp, $a0 8c: 00150083 or $sp, $a0, $zero ... Actually, it equals to a single instruction "sub.d $sp, $sp, $a0", but there is no proper condition to check it as a label like GCC, and so the beginning thought is not a good way. Essentially, there are two special frame pointer instructions which are "addi.d $fp, $sp, imm" and "addi.d $sp, $fp, imm", the first one points fp to the original stack top and the second one restores the original stack bottom from fp. Based on the above analysis, in order to avoid adding an arch-specific update_cfi_state(), we just add a member "frame_pointer" in the "struct symbol" as a label to avoid affecting the current normal case, then set it as true only if there is "addi.d $sp, $fp, imm". The last is to check this label for the two frame pointer instructions to change the cfa base and cfa offset in update_cfi_state(). Tested with the following two configs: (1) CONFIG_RANDOMIZE_KSTACK_OFFSET=y && CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT=n (2) CONFIG_RANDOMIZE_KSTACK_OFFSET=y && CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT=y By the way, there is no effect for x86 with this patch, tested on the x86 machine with Fedora 40 system. Cc: stable@vger.kernel.org # 6.9+ Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> | 1 年前 | |
objtool: Add elf_create_section_pair() When creating an annotation section, allocate the reloc section data at the beginning. This simplifies the data model a bit and also saves memory due to the removal of malloc() in elf_rebuild_reloc_section(). With allyesconfig + CONFIG_DEBUG_INFO: - Before: peak heap memory consumption: 53.49G - After: peak heap memory consumption: 49.02G Link: https://lore.kernel.org/r/048e908f3ede9b66c15e44672b6dda992b1dae3e.1685464332.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> | 3 年前 | |
objtool: Handle Clang RSP musical chairs stable inclusion from stable-v6.6.131 commit 1eed0199dbf41d6ac87243b38ebffbedc8454354 category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/ Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1eed0199dbf41d6ac87243b38ebffbedc8454354 -------------------------------- commit 1eed0199dbf41d6ac87243b38ebffbedc8454354 upstream. [ Upstream commit 7fdaa640c810cb42090a182c33f905bcc47a616a ] For no apparent reason (possibly related to CONFIG_KMSAN), Clang can randomly pass the value of RSP to other registers and then back again to RSP. Handle that accordingly. Fixes the following warnings: drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: undefined stack state drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: unknown CFA base reg -1 Reported-by: Arnd Bergmann <arnd@arndb.de> Closes: https://lore.kernel.org/90956545-2066-46e3-b547-10c884582eb0@app.fastmail.com Link: https://patch.msgid.link/240e6a172cc73292499334a3724d02ccb3247fc7.1772818491.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Wang Hai <wanghai38@huawei.com> | 1 个月前 |