linux-kernel - [PATCH v1 3/4] powerpc/process: Remove useless #ifdef CONFIG

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Message-Id: <698df8387555765b70ea42e4a7fa48141c309c1f.1597643221.git.christophe.leroy@csgroup.eu>
Date:   Mon, 17 Aug 2020 05:47:57 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v1 3/4] powerpc/process: Remove useless #ifdef CONFIG_SPE

cpu_has_feature(CPU_FTR_SPE) returns false when CONFIG_SPE is
not set.

There is no need to enclose the test in an #ifdef CONFIG_SPE.
Remove it.

CPU_FTR_SPE only exists on 32 bits. Define it as 0 on 64 bits.

We have a couple of places like:

 #ifdef CONFIG_SPE
	if (cpu_has_feature(CPU_FTR_SPE)) {
		do_something_that_requires_CONFIG_SPE
	} else {
		return -EINVAL;
	}
 #else
	return -EINVAL;
 #endif

Replace them by a cleaner version:

	if (cpu_has_feature(CPU_FTR_SPE)) {
 #ifdef CONFIG_SPE
		do_something_that_requires_CONFIG_SPE
 #endif
	} else {
		return -EINVAL;
	}

When CONFIG_SPE is not set, this resolves to an unconditional
return of -EINVAL

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/powerpc/include/asm/cputable.h |  1 +
 arch/powerpc/kernel/process.c       | 21 +++++++--------------
 2 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index fdddb822d564..cc21dbcc6794 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -165,6 +165,7 @@ static inline void cpu_feature_keys_init(void) { }
 #else	/* CONFIG_PPC32 */
 /* Define these to 0 for the sake of tests in common code */
 #define CPU_FTR_PPC_LE			(0)
+#define CPU_FTR_SPE			(0)
 #endif
 
 /*
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 360415689f8a..7090c99a60d9 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -413,10 +413,8 @@ static int __init init_msr_all_available(void)
 		msr_all_available |= MSR_VEC;
 	if (cpu_has_feature(CPU_FTR_VSX))
 		msr_all_available |= MSR_VSX;
-#ifdef CONFIG_SPE
 	if (cpu_has_feature(CPU_FTR_SPE))
 		msr_all_available |= MSR_SPE;
-#endif
 
 	return 0;
 }
@@ -446,10 +444,8 @@ void giveup_all(struct task_struct *tsk)
 #endif
 	if (usermsr & MSR_VEC)
 		__giveup_altivec(tsk);
-#ifdef CONFIG_SPE
 	if (usermsr & MSR_SPE)
 		__giveup_spe(tsk);
-#endif
 
 	msr_check_and_clear(msr_all_available);
 }
@@ -1843,7 +1839,6 @@ int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
 	 * fpexc_mode.  fpexc_mode is also used for setting FP exception
 	 * mode (asyn, precise, disabled) for 'Classic' FP. */
 	if (val & PR_FP_EXC_SW_ENABLE) {
-#ifdef CONFIG_SPE
 		if (cpu_has_feature(CPU_FTR_SPE)) {
 			/*
 			 * When the sticky exception bits are set
@@ -1857,16 +1852,15 @@ int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
 			 * anyway to restore the prctl settings from
 			 * the saved environment.
 			 */
+#ifdef CONFIG_SPE
 			tsk->thread.spefscr_last = mfspr(SPRN_SPEFSCR);
 			tsk->thread.fpexc_mode = val &
 				(PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
+#endif
 			return 0;
 		} else {
 			return -EINVAL;
 		}
-#else
-		return -EINVAL;
-#endif
 	}
 
 	/* on a CONFIG_SPE this does not hurt us.  The bits that
@@ -1887,8 +1881,7 @@ int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
 {
 	unsigned int val;
 
-	if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
-#ifdef CONFIG_SPE
+	if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE) {
 		if (cpu_has_feature(CPU_FTR_SPE)) {
 			/*
 			 * When the sticky exception bits are set
@@ -1902,15 +1895,15 @@ int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
 			 * anyway to restore the prctl settings from
 			 * the saved environment.
 			 */
+#ifdef CONFIG_SPE
 			tsk->thread.spefscr_last = mfspr(SPRN_SPEFSCR);
 			val = tsk->thread.fpexc_mode;
+#endif
 		} else
 			return -EINVAL;
-#else
-		return -EINVAL;
-#endif
-	else
+	} else {
 		val = __unpack_fe01(tsk->thread.fpexc_mode);
+	}
 	return put_user(val, (unsigned int __user *) adr);
 }
 
-- 
2.25.0