arm64: cpufeature: Fix the visibility of compat hwcaps

Commit 237405ebef58 ("arm64: cpufeature: Force HWCAP to be based on the
sysreg visible to user-space") forced the hwcaps to use sanitised
user-space view of the id registers. However, the ID register structures
used to select few compat cpufeatures (vfp, crc32, ...) are masked and
hence such hwcaps do not appear in /proc/cpuinfo anymore for PER_LINUX32
personality.

Add the ID register structures explicitly and set the relevant entry as
visible. As these ID registers are now of type visible so make them
available in 64-bit userspace by making necessary changes in register
emulation logic and documentation.

While at it, update the comment for structure ftr_generic_32bits[] which
lists the ID register that use it.

Fixes: 237405ebef58 ("arm64: cpufeature: Force HWCAP to be based on the sysreg visible to user-space")
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Link: https://lore.kernel.org/r/20221103082232.19189-1-amit.kachhap@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 37 insertions, 1 deletions

diff --git a/Documentation/arm64/cpu-feature-registers.rst b/Documentation/arm64/cpu-feature-registers.rst
index 04ba83e1965f..c7adc7897df6 100644
--- a/Documentation/arm64/cpu-feature-registers.rst
+++ b/Documentation/arm64/cpu-feature-registers.rst
@@ -92,7 +92,7 @@ operation if the source belongs to the supported system register space.
 
 The infrastructure emulates only the following system register space::
 
-	Op0=3, Op1=0, CRn=0, CRm=0,4,5,6,7
+	Op0=3, Op1=0, CRn=0, CRm=0,2,3,4,5,6,7
 
 (See Table C5-6 'System instruction encodings for non-Debug System
 register accesses' in ARMv8 ARM DDI 0487A.h, for the list of
@@ -293,6 +293,42 @@ infrastructure:
      | WFXT                         | [3-0]   |    y    |
      +------------------------------+---------+---------+
 
+  10) MVFR0_EL1 - AArch32 Media and VFP Feature Register 0
+
+     +------------------------------+---------+---------+
+     | Name                         |  bits   | visible |
+     +------------------------------+---------+---------+
+     | FPDP                         | [11-8]  |    y    |
+     +------------------------------+---------+---------+
+
+  11) MVFR1_EL1 - AArch32 Media and VFP Feature Register 1
+
+     +------------------------------+---------+---------+
+     | Name                         |  bits   | visible |
+     +------------------------------+---------+---------+
+     | SIMDFMAC                     | [31-28] |    y    |
+     +------------------------------+---------+---------+
+     | SIMDSP                       | [19-16] |    y    |
+     +------------------------------+---------+---------+
+     | SIMDInt                      | [15-12] |    y    |
+     +------------------------------+---------+---------+
+     | SIMDLS                       | [11-8]  |    y    |
+     +------------------------------+---------+---------+
+
+  12) ID_ISAR5_EL1 - AArch32 Instruction Set Attribute Register 5
+
+     +------------------------------+---------+---------+
+     | Name                         |  bits   | visible |
+     +------------------------------+---------+---------+
+     | CRC32                        | [19-16] |    y    |
+     +------------------------------+---------+---------+
+     | SHA2                         | [15-12] |    y    |
+     +------------------------------+---------+---------+
+     | SHA1                         | [11-8]  |    y    |
+     +------------------------------+---------+---------+
+     | AES                          | [7-4]   |    y    |
+     +------------------------------+---------+---------+
+
 
 Appendix I: Example
 -------------------