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| author | Jordan Niethe <jniethe5@gmail.com> | 2019-09-17 02:46:05 +0200 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-09-21 00:36:53 +0200 |
| commit | 13c7bb3c57dcfe779ea5b4b083f6c47753cc5327 (patch) | |
| tree | b1f09704685bd96151bf3f6882100d5ef0112069 /arch/powerpc/kernel/cpu_setup_power.S | |
| parent | powerpc: Fix definition of PCR bits to work with old binutils (diff) | |
| download | linux-13c7bb3c57dcfe779ea5b4b083f6c47753cc5327.tar.xz linux-13c7bb3c57dcfe779ea5b4b083f6c47753cc5327.zip | |
powerpc/64s: Set reserved PCR bits
Currently the reserved bits of the Processor Compatibility
Register (PCR) are cleared as per the Programming Note in Section
1.3.3 of version 3.0B of the Power ISA. This causes all new
architecture features to be made available when running on newer
processors with new architecture features added to the PCR as bits
must be set to disable a given feature.
For example to disable new features added as part of Version 2.07 of
the ISA the corresponding bit in the PCR needs to be set.
As new processor features generally require explicit kernel support
they should be disabled until such support is implemented. Therefore
kernels should set all unknown/reserved bits in the PCR such that any
new architecture features which the kernel does not currently know
about get disabled.
An update is planned to the ISA to clarify that the PCR is an
exception to the Programming Note on reserved bits in Section 1.3.3.
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190917004605.22471-2-alistair@popple.id.au
Diffstat (limited to 'arch/powerpc/kernel/cpu_setup_power.S')
| -rw-r--r-- | arch/powerpc/kernel/cpu_setup_power.S | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/cpu_setup_power.S b/arch/powerpc/kernel/cpu_setup_power.S index 3239a9fe6c1c..a460298c7ddb 100644 --- a/arch/powerpc/kernel/cpu_setup_power.S +++ b/arch/powerpc/kernel/cpu_setup_power.S @@ -23,6 +23,7 @@ _GLOBAL(__setup_cpu_power7) beqlr li r0,0 mtspr SPRN_LPID,r0 + LOAD_REG_IMMEDIATE(r0, PCR_MASK) mtspr SPRN_PCR,r0 mfspr r3,SPRN_LPCR li r4,(LPCR_LPES1 >> LPCR_LPES_SH) @@ -37,6 +38,7 @@ _GLOBAL(__restore_cpu_power7) beqlr li r0,0 mtspr SPRN_LPID,r0 + LOAD_REG_IMMEDIATE(r0, PCR_MASK) mtspr SPRN_PCR,r0 mfspr r3,SPRN_LPCR li r4,(LPCR_LPES1 >> LPCR_LPES_SH) @@ -54,6 +56,7 @@ _GLOBAL(__setup_cpu_power8) beqlr li r0,0 mtspr SPRN_LPID,r0 + LOAD_REG_IMMEDIATE(r0, PCR_MASK) mtspr SPRN_PCR,r0 mfspr r3,SPRN_LPCR ori r3, r3, LPCR_PECEDH @@ -76,6 +79,7 @@ _GLOBAL(__restore_cpu_power8) beqlr li r0,0 mtspr SPRN_LPID,r0 + LOAD_REG_IMMEDIATE(r0, PCR_MASK) mtspr SPRN_PCR,r0 mfspr r3,SPRN_LPCR ori r3, r3, LPCR_PECEDH @@ -98,6 +102,7 @@ _GLOBAL(__setup_cpu_power9) mtspr SPRN_PSSCR,r0 mtspr SPRN_LPID,r0 mtspr SPRN_PID,r0 + LOAD_REG_IMMEDIATE(r0, PCR_MASK) mtspr SPRN_PCR,r0 mfspr r3,SPRN_LPCR LOAD_REG_IMMEDIATE(r4, LPCR_PECEDH | LPCR_PECE_HVEE | LPCR_HVICE | LPCR_HEIC) @@ -123,6 +128,7 @@ _GLOBAL(__restore_cpu_power9) mtspr SPRN_PSSCR,r0 mtspr SPRN_LPID,r0 mtspr SPRN_PID,r0 + LOAD_REG_IMMEDIATE(r0, PCR_MASK) mtspr SPRN_PCR,r0 mfspr r3,SPRN_LPCR LOAD_REG_IMMEDIATE(r4, LPCR_PECEDH | LPCR_PECE_HVEE | LPCR_HVICE | LPCR_HEIC) |