b2812d031d
The current policies of breakpoints in x86 and SH are the following: - task bound breakpoints can only break on userspace addresses - cpu wide breakpoints can only break on kernel addresses The former rule prevents ptrace breakpoints to be set to trigger on kernel addresses, which is good. But as a side effect, we can't breakpoint on kernel addresses for task bound breakpoints. The latter rule simply makes no sense, there is no reason why we can't set breakpoints on userspace while performing cpu bound profiles. We want the following new policies: - task bound breakpoint can set userspace address breakpoints, with no particular privilege required. - task bound breakpoints can set kernelspace address breakpoints but must be privileged to do that. - cpu bound breakpoints can do what they want as they are privileged already. To implement these new policies, this patch checks if we are dealing with a kernel address breakpoint, if so and if the exclude_kernel parameter is set, we tell the user that the breakpoint is invalid, which makes a good generic ptrace protection. If we don't have exclude_kernel, ensure the user has the right privileges as kernel breakpoints are quite sensitive (risk of trap recursion attacks and global performance impacts). [ Paul Mundt: keep addr space check for sh signal delivery and fix double function declaration] Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Cc: K. Prasad <prasad@linux.vnet.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
72 lines
1.8 KiB
C
72 lines
1.8 KiB
C
#ifndef _I386_HW_BREAKPOINT_H
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#define _I386_HW_BREAKPOINT_H
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#ifdef __KERNEL__
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#define __ARCH_HW_BREAKPOINT_H
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/*
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* The name should probably be something dealt in
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* a higher level. While dealing with the user
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* (display/resolving)
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*/
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struct arch_hw_breakpoint {
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unsigned long address;
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u8 len;
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u8 type;
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};
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#include <linux/kdebug.h>
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#include <linux/percpu.h>
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#include <linux/list.h>
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/* Available HW breakpoint length encodings */
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#define X86_BREAKPOINT_LEN_1 0x40
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#define X86_BREAKPOINT_LEN_2 0x44
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#define X86_BREAKPOINT_LEN_4 0x4c
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#define X86_BREAKPOINT_LEN_EXECUTE 0x40
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#ifdef CONFIG_X86_64
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#define X86_BREAKPOINT_LEN_8 0x48
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#endif
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/* Available HW breakpoint type encodings */
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/* trigger on instruction execute */
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#define X86_BREAKPOINT_EXECUTE 0x80
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/* trigger on memory write */
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#define X86_BREAKPOINT_WRITE 0x81
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/* trigger on memory read or write */
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#define X86_BREAKPOINT_RW 0x83
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/* Total number of available HW breakpoint registers */
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#define HBP_NUM 4
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struct perf_event;
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struct pmu;
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extern int arch_check_bp_in_kernelspace(struct perf_event *bp);
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extern int arch_validate_hwbkpt_settings(struct perf_event *bp);
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extern int hw_breakpoint_exceptions_notify(struct notifier_block *unused,
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unsigned long val, void *data);
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int arch_install_hw_breakpoint(struct perf_event *bp);
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void arch_uninstall_hw_breakpoint(struct perf_event *bp);
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void hw_breakpoint_pmu_read(struct perf_event *bp);
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void hw_breakpoint_pmu_unthrottle(struct perf_event *bp);
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extern void
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arch_fill_perf_breakpoint(struct perf_event *bp);
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unsigned long encode_dr7(int drnum, unsigned int len, unsigned int type);
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int decode_dr7(unsigned long dr7, int bpnum, unsigned *len, unsigned *type);
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extern int arch_bp_generic_fields(int x86_len, int x86_type,
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int *gen_len, int *gen_type);
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extern struct pmu perf_ops_bp;
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#endif /* __KERNEL__ */
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#endif /* _I386_HW_BREAKPOINT_H */
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