From: Jordan Niethe <jniethe5@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: alistair@popple.id.au, npiggin@gmail.com, bala24@linux.ibm.com,
Jordan Niethe <jniethe5@gmail.com>,
dja@axtens.net
Subject: [PATCH v6 04/28] powerpc/xmon: Use bitwise calculations in_breakpoint_table()
Date: Tue, 28 Apr 2020 11:57:50 +1000 [thread overview]
Message-ID: <20200428015814.15380-5-jniethe5@gmail.com> (raw)
In-Reply-To: <20200428015814.15380-1-jniethe5@gmail.com>
A modulo operation is used for calculating the current offset from a
breakpoint within the breakpoint table. As instruction lengths are
always a power of 2, this can be replaced with a bitwise 'and'. The
current check for word alignment can be replaced with checking that the
lower 2 bits are not set.
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
v6: New to series
---
arch/powerpc/xmon/xmon.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index f7ce3ea8694c..e922cde99db2 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -856,8 +856,8 @@ static struct bpt *in_breakpoint_table(unsigned long nip, unsigned long *offp)
off = nip - (unsigned long) bpt_table;
if (off >= sizeof(bpt_table))
return NULL;
- *offp = off % BPT_SIZE;
- if (*offp != 0 && *offp != 4)
+ *offp = off & (BPT_SIZE - 1);
+ if (off & 3)
return NULL;
return bpts + (off / BPT_SIZE);
}
--
2.17.1
next prev parent reply other threads:[~2020-04-28 2:09 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-28 1:57 [PATCH v6 00/28] Initial Prefixed Instruction support Jordan Niethe
2020-04-28 1:57 ` [PATCH v6 01/28] powerpc/xmon: Remove store_inst() for patch_instruction() Jordan Niethe
2020-04-28 1:57 ` [PATCH v6 02/28] powerpc/xmon: Move breakpoint instructions to own array Jordan Niethe
2020-04-28 1:57 ` [PATCH v6 03/28] powerpc/xmon: Move breakpoints to text section Jordan Niethe
2020-04-28 5:19 ` Christophe Leroy
2020-04-28 5:30 ` Jordan Niethe
2020-04-28 5:36 ` Christophe Leroy
2020-04-29 2:45 ` Jordan Niethe
2020-04-28 1:57 ` Jordan Niethe [this message]
2020-04-28 1:57 ` [PATCH v6 05/28] powerpc: Change calling convention for create_branch() et. al Jordan Niethe
2020-04-28 1:57 ` [PATCH v6 06/28] powerpc: Use a macro for creating instructions from u32s Jordan Niethe
2020-04-28 1:57 ` [PATCH v6 07/28] powerpc: Use an accessor for instructions Jordan Niethe
2020-04-28 1:57 ` [PATCH v6 08/28] powerpc: Use a function for getting the instruction op code Jordan Niethe
2020-04-28 1:57 ` [PATCH v6 09/28] powerpc: Use a function for byte swapping instructions Jordan Niethe
2020-04-28 1:57 ` [PATCH v6 10/28] powerpc: Introduce functions for instruction equality Jordan Niethe
2020-04-29 1:59 ` Alistair Popple
2020-04-29 2:52 ` Jordan Niethe
2020-04-28 1:57 ` [PATCH v6 11/28] powerpc: Use a datatype for instructions Jordan Niethe
2020-04-29 2:02 ` Alistair Popple
2020-04-29 2:57 ` Jordan Niethe
2020-04-28 1:57 ` [PATCH v6 12/28] powerpc: Use a function for reading instructions Jordan Niethe
2020-04-28 1:57 ` [PATCH v6 13/28] powerpc: Add a probe_user_read_inst() function Jordan Niethe
2020-04-28 1:58 ` [PATCH v6 14/28] powerpc: Add a probe_kernel_read_inst() function Jordan Niethe
2020-04-28 1:58 ` [PATCH v6 15/28] powerpc/kprobes: Use patch_instruction() Jordan Niethe
2020-04-28 1:58 ` [PATCH v6 16/28] powerpc: Define and use __get_user_instr{, inatomic}() Jordan Niethe
2020-04-28 1:58 ` [PATCH v6 17/28] powerpc: Introduce a function for reporting instruction length Jordan Niethe
2020-04-28 1:58 ` [PATCH v6 18/28] powerpc/xmon: Use a function for reading instructions Jordan Niethe
2020-04-28 1:58 ` [PATCH v6 19/28] powerpc/xmon: Move insertion of breakpoint for xol'ing Jordan Niethe
2020-04-28 1:58 ` [PATCH v6 20/28] powerpc: Make test_translate_branch() independent of instruction length Jordan Niethe
2020-04-28 1:58 ` [PATCH v6 21/28] powerpc: Enable Prefixed Instructions Jordan Niethe
2020-04-28 1:58 ` [PATCH v6 22/28] powerpc: Define new SRR1 bits for a future ISA version Jordan Niethe
2020-04-28 1:58 ` [PATCH v6 23/28] powerpc: Add prefixed instructions to instruction data type Jordan Niethe
2020-04-28 1:58 ` [PATCH v6 24/28] powerpc: Test prefixed code patching Jordan Niethe
2020-04-28 1:58 ` [PATCH v6 25/28] powerpc: Test prefixed instructions in feature fixups Jordan Niethe
2020-04-28 1:58 ` [PATCH v6 26/28] powerpc: Support prefixed instructions in alignment handler Jordan Niethe
2020-04-28 1:58 ` [PATCH v6 27/28] powerpc sstep: Add support for prefixed load/stores Jordan Niethe
2020-04-28 1:58 ` [PATCH v6 28/28] powerpc sstep: Add support for prefixed fixed-point arithmetic Jordan Niethe
2020-04-28 10:06 ` [PATCH v6 00/28] Initial Prefixed Instruction support Balamuruhan S
2020-04-29 2:51 ` Jordan Niethe
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