This patch allows the LoongArch BPF JIT to handle recoverable memory
access errors generated by BPF_PROBE_MEM* instructions.
When a BPF program performs memory access operations, the instructions
it executes may trigger ADEM exceptions. The kernel’s built-in BPF
exception table mechanism (EX_TYPE_BPF) will generate corresponding
exception fixup entries in the JIT compilation phase; however, the
architecture-specific trap handling function needs to proactively call
the common fixup routine to achieve exception recovery.
do_ade(): fix EX_TYPE_BPF memory access exceptions for BPF programs,
ensure safe execution.
Relevant test cases: illegal address access tests in module_attach and
subprogs_extable of selftests/bpf.
Signed-off-by: Chenghao Duan <duanchenghao@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Now we use virtual addresses to fill CSR_MERRENTRY/CSR_TLBRENTRY, but
hardware hope physical addresses. Now it works well because the high
bits are ignored above PA_BITS (48 bits), but explicitly use physical
addresses can avoid potential bugs. So fix it.
Cc: stable@vger.kernel.org
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
After commit a934a57a42f64a4 ("scripts/misc-check: check missing #include
<linux/export.h> when W=1") and 7d95680d64ac8e836c ("scripts/misc-check:
check unnecessary #include <linux/export.h> when W=1"), we get some build
warnings with W=1:
arch/loongarch/kernel/acpi.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
arch/loongarch/kernel/alternative.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
arch/loongarch/kernel/kfpu.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
arch/loongarch/kernel/traps.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
arch/loongarch/kernel/unwind_guess.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
arch/loongarch/kernel/unwind_orc.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
arch/loongarch/kernel/unwind_prologue.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
arch/loongarch/lib/crc32-loongarch.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
arch/loongarch/lib/csum.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
arch/loongarch/kernel/elf.c: warning: EXPORT_SYMBOL() is not used, but #include <linux/export.h> is present
arch/loongarch/kernel/paravirt.c: warning: EXPORT_SYMBOL() is not used, but #include <linux/export.h> is present
arch/loongarch/pci/pci.c: warning: EXPORT_SYMBOL() is not used, but #include <linux/export.h> is present
So fix these build warnings for LoongArch.
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Currently, interrupts need to be disabled before single-step mode is
set, it requires that CSR_PRMD_PIE be cleared in save_local_irqflag()
which is called by setup_singlestep(), this is reasonable.
But in the first kprobe breakpoint exception, if the irq is enabled at
the beginning of do_bp(), it will not be disabled at the end of do_bp()
due to the CSR_PRMD_PIE has been cleared in save_local_irqflag(). So for
this case, it may corrupt exception context when restoring the exception
after do_bp() in handle_bp(), this is not reasonable.
In order to restore exception safely in handle_bp(), it needs to ensure
the irq is disabled at the end of do_bp(), so just add a local variable
to record the original interrupt status in the parent context, then use
it as the check condition to enable and disable irq in do_bp().
While at it, do the similar thing for other do_xyz() exception handlers
to make them more robust.
Fixes: 6d4cc40fb5f5 ("LoongArch: Add kprobes support")
Suggested-by: Jinyang He <hejinyang@loongson.cn>
Suggested-by: Huacai Chen <chenhuacai@loongson.cn>
Co-developed-by: Tianyang Zhang <zhangtianyang@loongson.cn>
Signed-off-by: Tianyang Zhang <zhangtianyang@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
1. Early return for user mode triggered exception with all types.
2. Give a chance to call fixup_exception() for default types (like
S390).
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Chenghao Duan