[PATCH V3 0/7] arm64/hw_breakpoint: Enable FEAT_Debugv8p9

Anshuman Khandual
2024-12-16T04:08:41Z

This series enables FEAT_Debugv8p9 thus extending breakpoint and watchpoint
support upto 64. This series is based on v6.13-rc3 although this depends on
FEAT_FGT2 FGU series posted earlier, for MDSELR_EL1 handling in various KVM
guest configurations.

https://lore.kernel.org/all/20241210055311.780688-3-anshuman.khandual@arm.com/

Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: kvmarm@lists.linux.dev
Cc: linux-kernel@vger.kernel.org

Changes in V3:

- Marked ID_AA64DFR1_EL1.ABLE as FTR_NONSTRICT in ftr_id_aa64dfr1[]
- Dropped MDCR_EL3.TDA boot requirement from documentation (separate series)
- Dropped MDCR_EL2_EBWE definition as MDCR_EL2 is now defined in tools sysreg
- Used SYS_FIELD_PREP() in read_wb_reg() and write_wb_reg()
- Added MAX_PER_BANK based BUILD_BUG_ON() tests in arch_hw_breakpoint_init()
- Dropped local variables i.e mdsel_bank and index
- Derived bank and index from MAX_PER_BANK as required

Changes in V2:

https://lore.kernel.org/all/20241028053426.2486633-1-anshuman.khandual@arm.com/

Following changes have been made per review comments from Mark Rutland

- Orr MDCR_EL2_EBWE directly without an intermittent register
- Alphabetically order header files in debug-monitors.c
- Dropped embwe_ref_count mechanism
- Dropped preempt_enable() from AARCH64_DBG_READ
- Dropped preempt_disable() from AARCH64_DBG_WRITE
- Dropped set_bank_index()
- Renamed read/write_wb_reg() as __read/__write_wb_reg()
- Modified read/write_wb_reg() to have MDSELR_E1 based banked read/write
- Added required sysreg tools patches from KVM FEAT_FGT2 series for build

Changes in V1:

https://lore.kernel.org/all/20241001043602.1116991-1-anshuman.khandual@arm.com/

- Changed FTR_STRICT to FTR_NONSTRICT for the following ID_AA64DFR1_EL1
register fields - ABL_CMPs, DPFZS, PMICNTR, CTX_CMPs, WRPs and BRPs

Changes in RFC V2:

https://lore.kernel.org/linux-arm-kernel/20240620092607.267132-1-anshuman.khandual@arm.com/

- This series has been split from RFC V1 dealing only with arm64 breakpoints
- Restored back DBG_MDSCR_MASK definition (unrelated change)
- Added preempt_disable()/enable() blocks between selecting banks and registers

Changes in RFC:

https://lore.kernel.org/all/20240405080008.1225223-1-anshuman.khandual@arm.com/

Anshuman Khandual (7):
arm64/sysreg: Update register fields for ID_AA64MMFR0_EL1
arm64/sysreg: Add register fields for MDSELR_EL1
arm64/sysreg: Add register fields for HDFGRTR2_EL2
arm64/sysreg: Add register fields for HDFGWTR2_EL2
arm64/cpufeature: Add field details for ID_AA64DFR1_EL1 register
arm64/boot: Enable EL2 requirements for FEAT_Debugv8p9
arm64/hw_breakpoint: Enable FEAT_Debugv8p9

Documentation/arch/arm64/booting.rst | 18 +++++++
arch/arm64/include/asm/debug-monitors.h | 1 +
arch/arm64/include/asm/el2_setup.h | 26 +++++++++
arch/arm64/include/asm/hw_breakpoint.h | 47 +++++++++++++----
arch/arm64/kernel/cpufeature.c | 21 ++++++--
arch/arm64/kernel/debug-monitors.c | 15 ++++--
arch/arm64/kernel/hw_breakpoint.c | 48 ++++++++++++++++-
arch/arm64/tools/sysreg | 70 +++++++++++++++++++++++++
8 files changed, 225 insertions(+), 21 deletions(-)

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2.25.1