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fb978ca207
Generic implementation fails to remove breakpoints after init
when CONFIG_STRICT_KERNEL_RWX is selected:
[ 13.251285] KGDB: BP remove failed: c001c338
[ 13.259587] kgdbts: ERROR PUT: end of test buffer on 'do_fork_test' line 8 expected OK got $E14#aa
[ 13.268969] KGDB: re-enter exception: ALL breakpoints killed
[ 13.275099] CPU: 0 PID: 1 Comm: init Not tainted 4.18.0-g82bbb913ffd8 #860
[ 13.282836] Call Trace:
[ 13.285313] [c60e1ba0] [c0080ef0] kgdb_handle_exception+0x6f4/0x720 (unreliable)
[ 13.292618] [c60e1c30] [c000e97c] kgdb_handle_breakpoint+0x3c/0x98
[ 13.298709] [c60e1c40] [c000af54] program_check_exception+0x104/0x700
[ 13.305083] [c60e1c60] [c000e45c] ret_from_except_full+0x0/0x4
[ 13.310845] [c60e1d20] [c02a22ac] run_simple_test+0x2b4/0x2d4
[ 13.316532] [c60e1d30] [c0081698] put_packet+0xb8/0x158
[ 13.321694] [c60e1d60] [c00820b4] gdb_serial_stub+0x230/0xc4c
[ 13.327374] [c60e1dc0] [c0080af8] kgdb_handle_exception+0x2fc/0x720
[ 13.333573] [c60e1e50] [c000e928] kgdb_singlestep+0xb4/0xcc
[ 13.339068] [c60e1e70] [c000ae1c] single_step_exception+0x90/0xac
[ 13.345100] [c60e1e80] [c000e45c] ret_from_except_full+0x0/0x4
[ 13.350865] [c60e1f40] [c000e11c] ret_from_syscall+0x0/0x38
[ 13.356346] Kernel panic - not syncing: Recursive entry to debugger
This patch creates powerpc specific version of
kgdb_arch_set_breakpoint() and kgdb_arch_remove_breakpoint()
using patch_instruction()
Fixes: 1e0fc9d1eb ("powerpc/Kconfig: Enable STRICT_KERNEL_RWX for some configs")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
67 lines
2.1 KiB
C
67 lines
2.1 KiB
C
/*
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* The PowerPC (32/64) specific defines / externs for KGDB. Based on
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* the previous 32bit and 64bit specific files, which had the following
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* copyrights:
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*
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* PPC64 Mods (C) 2005 Frank Rowand (frowand@mvista.com)
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* PPC Mods (C) 2004 Tom Rini (trini@mvista.com)
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* PPC Mods (C) 2003 John Whitney (john.whitney@timesys.com)
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* PPC Mods (C) 1998 Michael Tesch (tesch@cs.wisc.edu)
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*
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*
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* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
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* Author: Tom Rini <trini@kernel.crashing.org>
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*
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* 2006 (c) MontaVista Software, Inc. This file is licensed under
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* the terms of the GNU General Public License version 2. This program
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* is licensed "as is" without any warranty of any kind, whether express
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* or implied.
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*/
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#ifdef __KERNEL__
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#ifndef __POWERPC_KGDB_H__
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#define __POWERPC_KGDB_H__
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#ifndef __ASSEMBLY__
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#define BREAK_INSTR_SIZE 4
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#define BUFMAX ((NUMREGBYTES * 2) + 512)
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#define OUTBUFMAX ((NUMREGBYTES * 2) + 512)
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#define BREAK_INSTR 0x7d821008 /* twge r2, r2 */
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static inline void arch_kgdb_breakpoint(void)
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{
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asm(stringify_in_c(.long BREAK_INSTR));
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}
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#define CACHE_FLUSH_IS_SAFE 1
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#define DBG_MAX_REG_NUM 70
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/* The number bytes of registers we have to save depends on a few
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* things. For 64bit we default to not including vector registers and
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* vector state registers. */
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#ifdef CONFIG_PPC64
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/*
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* 64 bit (8 byte) registers:
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* 32 gpr, 32 fpr, nip, msr, link, ctr
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* 32 bit (4 byte) registers:
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* ccr, xer, fpscr
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*/
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#define NUMREGBYTES ((68 * 8) + (3 * 4))
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#define NUMCRITREGBYTES 184
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#else /* CONFIG_PPC32 */
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/* On non-E500 family PPC32 we determine the size by picking the last
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* register we need, but on E500 we skip sections so we list what we
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* need to store, and add it up. */
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#ifndef CONFIG_E500
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#define MAXREG (PT_FPSCR+1)
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#else
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/* 32 GPRs (8 bytes), nip, msr, ccr, link, ctr, xer, acc (8 bytes), spefscr*/
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#define MAXREG ((32*2)+6+2+1)
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#endif
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#define NUMREGBYTES (MAXREG * sizeof(int))
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/* CR/LR, R1, R2, R13-R31 inclusive. */
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#define NUMCRITREGBYTES (23 * sizeof(int))
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#endif /* 32/64 */
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#endif /* !(__ASSEMBLY__) */
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#endif /* !__POWERPC_KGDB_H__ */
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#endif /* __KERNEL__ */
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