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| author | Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> | 2018-06-07 15:22:02 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-10-20 13:26:43 +1100 |
| commit | 7cd01b08d35f1b7d55686ed8cd57c94d3406ec8f (patch) | |
| tree | ba2112d797cf4e9ba7c690fe9bbe07dad8d5a873 /arch/powerpc/lib | |
| parent | b4d16ab58c41ff0125822464bdff074cebd0fe47 (diff) | |
| download | linux-7cd01b08d35f1b7d55686ed8cd57c94d3406ec8f.tar.bz2 | |
powerpc: Add support for function error injection
We implement regs_set_return_value() and override_function_with_return()
for this purpose.
On powerpc, a return from a function (blr) just branches to the location
contained in the link register. So, we can just update pt_regs rather
than redirecting execution to a dummy function that returns.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/lib')
| -rw-r--r-- | arch/powerpc/lib/Makefile | 2 | ||||
| -rw-r--r-- | arch/powerpc/lib/error-inject.c | 16 |
2 files changed, 18 insertions, 0 deletions
diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile index 703afa1808ed..3bf9fc6fd36c 100644 --- a/arch/powerpc/lib/Makefile +++ b/arch/powerpc/lib/Makefile @@ -12,6 +12,8 @@ obj-y += string.o alloc.o code-patching.o feature-fixups.o obj-$(CONFIG_PPC32) += div64.o copy_32.o crtsavres.o strlen_32.o +obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o + # See corresponding test in arch/powerpc/Makefile # 64-bit linker creates .sfpr on demand for final link (vmlinux), # so it is only needed for modules, and only for older linkers which diff --git a/arch/powerpc/lib/error-inject.c b/arch/powerpc/lib/error-inject.c new file mode 100644 index 000000000000..407b992fb02f --- /dev/null +++ b/arch/powerpc/lib/error-inject.c @@ -0,0 +1,16 @@ +// SPDX-License-Identifier: GPL-2.0+ + +#include <linux/error-injection.h> +#include <linux/kprobes.h> +#include <linux/uaccess.h> + +void override_function_with_return(struct pt_regs *regs) +{ + /* + * Emulate 'blr'. 'regs' represents the state on entry of a predefined + * function in the kernel/module, captured on a kprobe. We don't need + * to worry about 32-bit userspace on a 64-bit kernel. + */ + regs->nip = regs->link; +} +NOKPROBE_SYMBOL(override_function_with_return); |