This commit continues adding support for the Branch History
Rolling Buffer (BHRB) as is provided starting with the P8
processor and continuing with its successors. This commit
is limited to the recording and filtering of taken branches.
The following changes were made:
- Enabled functionality on P10 processors only due to
performance impact seen with P8 and P9 where it is not
disabled for non problem state branches.
- Added a BHRB buffer for storing branch instruction and
target addresses for taken branches
- Renamed gen_update_cfar to gen_update_branch_history and
added a 'target' parameter to hold the branch target
address and 'inst_type' parameter to use for filtering
- Added TCG code to gen_update_branch_history that stores
data to the BHRB and updates the BHRB offset.
- Added BHRB resource initialization and reset functions
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Glenn Miles <milesg@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Allow the name 'cpu_env' to be used for something else.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Now that gen_icount_io_start() is a simple wrapper to
translator_io_start(), inline it.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230602095439.48102-1-philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
An Event-Based Branch (EBB) allows applications to change the NIA when a
event-based exception occurs. Event-based exceptions are enabled by
setting the Branch Event Status and Control Register (BESCR). If the
event-based exception is enabled when the exception occurs, an EBB
happens.
The following operations happens during an EBB:
- Global Enable (GE) bit of BESCR is set to 0;
- bits 0-61 of the Event-Based Branch Return Register (EBBRR) are set
to the the effective address of the NIA that would have executed if the EBB
didn't happen;
- Instruction fetch and execution will continue in the effective address
contained in the Event-Based Branch Handler Register (EBBHR).
The EBB Handler will process the event and then execute the Return From
Event-Based Branch (rfebb) instruction. rfebb sets BESCR_GE and then
redirects execution to the address pointed in EBBRR. This process is
described in the PowerISA v3.1, Book II, Chapter 6 [1].
This patch implements the rfebb instruction. Descriptions of all
relevant BESCR bits are also added - this patch is only using BESCR_GE,
but the next patches will use the remaining bits.
[1] https://wiki.raptorcs.com/w/images/f/f5/PowerISA_public.v3.1.pdf
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20211201151734.654994-9-danielhb413@gmail.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
