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Commit f6a745c5 authored by Amit Daniel Kachhap's avatar Amit Daniel Kachhap Committed by Greg Kroah-Hartman
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arm64: cpufeature: Fix the visibility of compat hwcaps 



commit 85f1506337f0c79a4955edfeee86a18628e3735f upstream.

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: default avatarJames Morse <james.morse@arm.com>
Signed-off-by: default avatarAmit Daniel Kachhap <amit.kachhap@arm.com>
Link: https://lore.kernel.org/r/20221103082232.19189-1-amit.kachhap@arm.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a256d019

Documentation/arm64/cpu-feature-registers.rst

+37 −1
Original line number Diff line number Diff line
@@ -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
@@ -167,6 +167,42 @@ infrastructure: 
     | EL0                          | [3-0]   |    n    |

     +------------------------------+---------+---------+



  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    |

     +------------------------------+---------+---------+





  3) MIDR_EL1 - Main ID Register

arch/arm64/kernel/cpufeature.c

+33 −9
Original line number Diff line number Diff line
@@ -292,6 +292,30 @@ static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = { 
	ARM64_FTR_END,

};



static const struct arm64_ftr_bits ftr_mvfr0[] = {

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, MVFR0_FPROUND_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, MVFR0_FPSHVEC_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, MVFR0_FPSQRT_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, MVFR0_FPDIVIDE_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, MVFR0_FPTRAP_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, MVFR0_FPDP_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, MVFR0_FPSP_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, MVFR0_SIMD_SHIFT, 4, 0),

	ARM64_FTR_END,

};



static const struct arm64_ftr_bits ftr_mvfr1[] = {

	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, MVFR1_SIMDFMAC_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, MVFR1_FPHP_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, MVFR1_SIMDHP_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, MVFR1_SIMDSP_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, MVFR1_SIMDINT_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, MVFR1_SIMDLS_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, MVFR1_FPDNAN_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, MVFR1_FPFTZ_SHIFT, 4, 0),

	ARM64_FTR_END,

};



static const struct arm64_ftr_bits ftr_mvfr2[] = {

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 4, 4, 0),		/* FPMisc */

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 0, 4, 0),		/* SIMDMisc */
@@ -307,10 +331,10 @@ static const struct arm64_ftr_bits ftr_dczid[] = { 


static const struct arm64_ftr_bits ftr_id_isar5[] = {

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_RDM_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_CRC32_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SHA2_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SHA1_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_AES_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_CRC32_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SHA2_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SHA1_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_AES_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SEVL_SHIFT, 4, 0),

	ARM64_FTR_END,

};
@@ -350,7 +374,7 @@ static const struct arm64_ftr_bits ftr_zcr[] = { 
 * Common ftr bits for a 32bit register with all hidden, strict

 * attributes, with 4bit feature fields and a default safe value of

 * 0. Covers the following 32bit registers:

 * id_isar[0-4], id_mmfr[1-3], id_pfr1, mvfr[0-1]

 * id_isar[1-3], id_mmfr[1-3]

 */

static const struct arm64_ftr_bits ftr_generic_32bits[] = {

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
@@ -405,8 +429,8 @@ static const struct __ftr_reg_entry { 
	ARM64_FTR_REG(SYS_ID_MMFR4_EL1, ftr_id_mmfr4),



	/* Op1 = 0, CRn = 0, CRm = 3 */

	ARM64_FTR_REG(SYS_MVFR0_EL1, ftr_generic_32bits),

	ARM64_FTR_REG(SYS_MVFR1_EL1, ftr_generic_32bits),

	ARM64_FTR_REG(SYS_MVFR0_EL1, ftr_mvfr0),

	ARM64_FTR_REG(SYS_MVFR1_EL1, ftr_mvfr1),

	ARM64_FTR_REG(SYS_MVFR2_EL1, ftr_mvfr2),



	/* Op1 = 0, CRn = 0, CRm = 4 */
@@ -2182,7 +2206,7 @@ static void __maybe_unused cpu_enable_cnp(struct arm64_cpu_capabilities const *c 


/*

 * We emulate only the following system register space.

 * Op0 = 0x3, CRn = 0x0, Op1 = 0x0, CRm = [0, 4 - 7]

 * Op0 = 0x3, CRn = 0x0, Op1 = 0x0, CRm = [0, 2 - 7]

 * See Table C5-6 System instruction encodings for System register accesses,

 * ARMv8 ARM(ARM DDI 0487A.f) for more details.

 */
@@ -2192,7 +2216,7 @@ static inline bool __attribute_const__ is_emulated(u32 id) 
		sys_reg_CRn(id) == 0x0 &&

		sys_reg_Op1(id) == 0x0 &&

		(sys_reg_CRm(id) == 0 ||

		 ((sys_reg_CRm(id) >= 4) && (sys_reg_CRm(id) <= 7))));

		 ((sys_reg_CRm(id) >= 2) && (sys_reg_CRm(id) <= 7))));

}



/*