From: Jordan Niethe <jniethe5@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: alistair@popple.id.au, npiggin@gmail.com, bala24@linux.ibm.com,
naveen.n.rao@linux.vnet.ibm.com,
Jordan Niethe <jniethe5@gmail.com>,
dja@axtens.net
Subject: [PATCH v7 04/28] powerpc/xmon: Use bitwise calculations in_breakpoint_table()
Date: Fri, 1 May 2020 13:41:56 +1000 [thread overview]
Message-ID: <20200501034220.8982-5-jniethe5@gmail.com> (raw)
In-Reply-To: <20200501034220.8982-1-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 bbfea22f4a96..e122f0c8a044 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -857,8 +857,8 @@ 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:[~2020-05-01 3:52 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-01 3:41 [PATCH v7 00/28] Initial Prefixed Instruction support Jordan Niethe
2020-05-01 3:41 ` [PATCH v7 01/28] powerpc/xmon: Remove store_inst() for patch_instruction() Jordan Niethe
2020-05-01 3:41 ` [PATCH v7 02/28] powerpc/xmon: Move breakpoint instructions to own array Jordan Niethe
2020-05-04 5:41 ` Alistair Popple
2020-05-04 5:52 ` Jordan Niethe
2020-05-01 3:41 ` [PATCH v7 03/28] powerpc/xmon: Move breakpoints to text section Jordan Niethe
2020-05-01 3:41 ` Jordan Niethe [this message]
2020-05-04 5:41 ` [PATCH v7 04/28] powerpc/xmon: Use bitwise calculations in_breakpoint_table() Alistair Popple
2020-05-05 7:08 ` Michael Ellerman
2020-05-05 7:31 ` Jordan Niethe
2020-05-01 3:41 ` [PATCH v7 05/28] powerpc: Change calling convention for create_branch() et. al Jordan Niethe
2020-05-04 2:55 ` Alistair Popple
2020-05-01 3:41 ` [PATCH v7 06/28] powerpc: Use a macro for creating instructions from u32s Jordan Niethe
2020-05-04 5:54 ` Alistair Popple
2020-05-01 3:41 ` [PATCH v7 07/28] powerpc: Use an accessor for instructions Jordan Niethe
2020-05-01 3:42 ` [PATCH v7 08/28] powerpc: Use a function for getting the instruction op code Jordan Niethe
2020-05-04 8:01 ` Alistair Popple
2020-05-01 3:42 ` [PATCH v7 09/28] powerpc: Use a function for byte swapping instructions Jordan Niethe
2020-05-01 3:42 ` [PATCH v7 10/28] powerpc: Introduce functions for instruction equality Jordan Niethe
2020-05-01 3:42 ` [PATCH v7 11/28] powerpc: Use a datatype for instructions Jordan Niethe
2020-05-02 14:29 ` kbuild test robot
2020-05-01 3:42 ` [PATCH v7 12/28] powerpc: Use a function for reading instructions Jordan Niethe
2020-05-04 8:26 ` Alistair Popple
2020-05-01 3:42 ` [PATCH v7 13/28] powerpc: Add a probe_user_read_inst() function Jordan Niethe
2020-05-04 8:30 ` Alistair Popple
2020-05-01 3:42 ` [PATCH v7 14/28] powerpc: Add a probe_kernel_read_inst() function Jordan Niethe
2020-05-04 9:24 ` Alistair Popple
2020-05-01 3:42 ` [PATCH v7 15/28] powerpc/kprobes: Use patch_instruction() Jordan Niethe
2020-05-05 1:41 ` Alistair Popple
2020-05-01 3:42 ` [PATCH v7 16/28] powerpc: Define and use __get_user_instr{, inatomic}() Jordan Niethe
2020-05-05 1:46 ` Alistair Popple
2020-05-01 3:42 ` [PATCH v7 17/28] powerpc: Introduce a function for reporting instruction length Jordan Niethe
2020-05-05 2:02 ` Alistair Popple
2020-05-01 3:42 ` [PATCH v7 18/28] powerpc/xmon: Use a function for reading instructions Jordan Niethe
2020-05-05 2:07 ` Alistair Popple
2020-05-01 3:42 ` [PATCH v7 19/28] powerpc/xmon: Move insertion of breakpoint for xol'ing Jordan Niethe
2020-05-05 2:19 ` Alistair Popple
2020-05-01 3:42 ` [PATCH v7 20/28] powerpc: Make test_translate_branch() independent of instruction length Jordan Niethe
2020-05-05 2:40 ` Alistair Popple
2020-05-01 3:42 ` [PATCH v7 21/28] powerpc: Enable Prefixed Instructions Jordan Niethe
2020-05-01 3:42 ` [PATCH v7 22/28] powerpc: Define new SRR1 bits for a future ISA version Jordan Niethe
2020-05-05 2:49 ` Alistair Popple
2020-05-01 3:42 ` [PATCH v7 23/28] powerpc: Add prefixed instructions to instruction data type Jordan Niethe
2020-05-05 6:04 ` Alistair Popple
2020-05-01 3:42 ` [PATCH v7 24/28] powerpc: Test prefixed code patching Jordan Niethe
2020-05-05 6:08 ` Alistair Popple
2020-05-01 3:42 ` [PATCH v7 25/28] powerpc: Test prefixed instructions in feature fixups Jordan Niethe
2020-05-05 7:15 ` Alistair Popple
2020-05-05 7:34 ` Jordan Niethe
2020-05-01 3:42 ` [PATCH v7 26/28] powerpc: Support prefixed instructions in alignment handler Jordan Niethe
2020-05-05 7:17 ` Alistair Popple
2020-05-01 3:42 ` [PATCH v7 27/28] powerpc sstep: Add support for prefixed load/stores Jordan Niethe
2020-05-01 3:42 ` [PATCH v7 28/28] powerpc sstep: Add support for prefixed fixed-point arithmetic Jordan Niethe
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