linux-kernel - [PATCHv4 02/19] arm64: move SCTLR_EL{1,2} assertions to <asm/sysreg.h>

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Date:   Mon,  2 Jul 2018 12:03:58 +0100
From:   Mark Rutland <mark.rutland@....com>
To:     linux-arm-kernel@...ts.infradead.org, will.deacon@....com
Cc:     linux-kernel@...r.kernel.org, catalin.marinas@....com,
        dave.martin@....com, hch@...radead.org, james.morse@....com,
        linux@...inikbrodowski.net, linux-fsdevel@...r.kernel.org,
        marc.zyngier@....com, mark.rutland@....com, viro@...iv.linux.org.uk
Subject: [PATCHv4 02/19] arm64: move SCTLR_EL{1,2} assertions to <asm/sysreg.h>

Currently we assert that the SCTLR_EL{1,2}_{SET,CLEAR} bits are
self-consistent with an assertion in config_sctlr_el1(). This is a bit
unusual, since config_sctlr_el1() doesn't make use of these definitions,
and is far away from the definitions themselves.

We can use the CPP #error directive to have equivalent assertions in
<asm/sysreg.h>, next to the definitions of the set/clear bits, which is
a bit clearer and simpler.

At the same time, lets fill in the upper 32 bits for both registers in
their respective RES0 definitions. This could be a little nicer with
GENMASK_ULL(63, 32), but this currently lives in <linux/bitops.h>, which
cannot safely be included from assembly, as <asm/sysreg.h> can.

Note the when the preprocessor evaluates an expression for an #if
directive, all signed or unsigned values are treated as intmax_t or
uintmax_t respectively. To avoid ambiguity, we define explicitly define
the mask of all 64 bits.

Signed-off-by: Mark Rutland <mark.rutland@....com>
Acked-by: Catalin Marinas <catalin.marinas@....com>
Cc: Dave Martin <dave.martin@....com>
Cc: James Morse <james.morse@....com>
Cc: Will Deacon <will.deacon@....com>
---
 arch/arm64/include/asm/sysreg.h | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index a8f84812c6e8..fefc17dae8ee 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -436,7 +436,8 @@
 #define SCTLR_EL2_RES0	((1 << 6)  | (1 << 7)  | (1 << 8)  | (1 << 9)  | \
 			 (1 << 10) | (1 << 13) | (1 << 14) | (1 << 15) | \
 			 (1 << 17) | (1 << 20) | (1 << 24) | (1 << 26) | \
-			 (1 << 27) | (1 << 30) | (1 << 31))
+			 (1 << 27) | (1 << 30) | (1 << 31) | \
+			 (0xffffffffUL << 32))
 
 #ifdef CONFIG_CPU_BIG_ENDIAN
 #define ENDIAN_SET_EL2		SCTLR_ELx_EE
@@ -452,9 +453,9 @@
 			 SCTLR_ELx_SA     | SCTLR_ELx_I    | SCTLR_ELx_WXN | \
 			 ENDIAN_CLEAR_EL2 | SCTLR_EL2_RES0)
 
-/* Check all the bits are accounted for */
-#define SCTLR_EL2_BUILD_BUG_ON_MISSING_BITS	BUILD_BUG_ON((SCTLR_EL2_SET ^ SCTLR_EL2_CLEAR) != ~0)
-
+#if (SCTLR_EL2_SET ^ SCTLR_EL2_CLEAR) != 0xffffffffffffffff
+#error "Inconsistent SCTLR_EL2 set/clear bits"
+#endif
 
 /* SCTLR_EL1 specific flags. */
 #define SCTLR_EL1_UCI		(1 << 26)
@@ -473,7 +474,8 @@
 #define SCTLR_EL1_RES1	((1 << 11) | (1 << 20) | (1 << 22) | (1 << 28) | \
 			 (1 << 29))
 #define SCTLR_EL1_RES0  ((1 << 6)  | (1 << 10) | (1 << 13) | (1 << 17) | \
-			 (1 << 27) | (1 << 30) | (1 << 31))
+			 (1 << 27) | (1 << 30) | (1 << 31) | \
+			 (0xffffffffUL << 32))
 
 #ifdef CONFIG_CPU_BIG_ENDIAN
 #define ENDIAN_SET_EL1		(SCTLR_EL1_E0E | SCTLR_ELx_EE)
@@ -492,8 +494,9 @@
 			 SCTLR_EL1_UMA | SCTLR_ELx_WXN     | ENDIAN_CLEAR_EL1 |\
 			 SCTLR_EL1_RES0)
 
-/* Check all the bits are accounted for */
-#define SCTLR_EL1_BUILD_BUG_ON_MISSING_BITS	BUILD_BUG_ON((SCTLR_EL1_SET ^ SCTLR_EL1_CLEAR) != ~0)
+#if (SCTLR_EL1_SET ^ SCTLR_EL1_CLEAR) != 0xffffffffffffffff
+#error "Inconsistent SCTLR_EL1 set/clear bits"
+#endif
 
 /* id_aa64isar0 */
 #define ID_AA64ISAR0_TS_SHIFT		52
@@ -743,9 +746,6 @@ static inline void config_sctlr_el1(u32 clear, u32 set)
 {
 	u32 val;
 
-	SCTLR_EL2_BUILD_BUG_ON_MISSING_BITS;
-	SCTLR_EL1_BUILD_BUG_ON_MISSING_BITS;
-
 	val = read_sysreg(sctlr_el1);
 	val &= ~clear;
 	val |= set;
-- 
2.11.0