[PATCH 4/9] MIPS: VDSO: Only map the data pages when the vDSO is used

[Thomas Weißschuh]

A future change will make it possible to disable the time-related vDSO.
In that case there is no point in calling into the datastore.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
---
 arch/mips/Kconfig       |  2 +-
 arch/mips/kernel/vdso.c | 12 +++++++-----
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index af610af7ed08..3a01cc85bd6a 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -74,7 +74,6 @@ config MIPS
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_TRACER
 	select HAVE_GCC_PLUGINS
-	select HAVE_GENERIC_VDSO
 	select HAVE_IOREMAP_PROT
 	select HAVE_IRQ_EXIT_ON_IRQ_STACK
 	select HAVE_IRQ_TIME_ACCOUNTING
@@ -3172,6 +3171,7 @@ config MIPS_GENERIC_GETTIMEOFDAY
 	def_bool y
 	select GENERIC_GETTIMEOFDAY
 	select GENERIC_TIME_VSYSCALL
+	select HAVE_GENERIC_VDSO
 
 menu "CPU Power Management"
 
diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c
index 2fa4df3e46e4..bd1fc17d3975 100644
--- a/arch/mips/kernel/vdso.c
+++ b/arch/mips/kernel/vdso.c
@@ -129,7 +129,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	 * This ensures that when the kernel updates the VDSO data userland
 	 * will observe it without requiring cache invalidations.
 	 */
-	if (cpu_has_dc_aliases) {
+	if (cpu_has_dc_aliases && IS_ENABLED(CONFIG_HAVE_GENERIC_VDSO)) {
 		base = __ALIGN_MASK(base, shm_align_mask);
 		base += ((unsigned long)vdso_k_time_data - gic_size) & shm_align_mask;
 	}
@@ -137,10 +137,12 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	data_addr = base + gic_size;
 	vdso_addr = data_addr + VDSO_NR_PAGES * PAGE_SIZE;
 
-	vma = vdso_install_vvar_mapping(mm, data_addr);
-	if (IS_ERR(vma)) {
-		ret = PTR_ERR(vma);
-		goto out;
+	if (IS_ENABLED(CONFIG_HAVE_GENERIC_VDSO)) {
+		vma = vdso_install_vvar_mapping(mm, data_addr);
+		if (IS_ERR(vma)) {
+			ret = PTR_ERR(vma);
+			goto out;
+		}
 	}
 
 	/* Map GIC user page. */

-- 
2.54.0