Revert "RISC-V: vDSO: Wire up getrandom() vDSO implementation"

This has been on -next for a bit, but it's broken and there's already a
v2.  So I'm reverting it to avoid more rebasing.

This reverts commit 8907952.

Link: https://lore.kernel.org/r/20250602173315.20228-1-palmer@dabbelt.com
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>

Author: palmer-dabbelt

arch/riscv/Kconfig

@@ -218,7 +218,6 @@ config RISCV
 	select THREAD_INFO_IN_TASK
 	select TRACE_IRQFLAGS_SUPPORT
 	select UACCESS_MEMCPY if !MMU
-	select VDSO_GETRANDOM if HAVE_GENERIC_VDSO
 	select USER_STACKTRACE_SUPPORT
 	select ZONE_DMA32 if 64BIT
 

arch/riscv/include/asm/vdso/getrandom.h

@@ -13,17 +13,9 @@ vdso-syms += flush_icache
 vdso-syms += hwprobe
 vdso-syms += sys_hwprobe
 
-ifdef CONFIG_VDSO_GETRANDOM
-vdso-syms += getrandom
-endif
-
 # Files to link into the vdso
 obj-vdso = $(patsubst %, %.o, $(vdso-syms)) note.o
 
-ifdef CONFIG_VDSO_GETRANDOM
-obj-vdso += vgetrandom-chacha.o
-endif
-
 ccflags-y := -fno-stack-protector
 ccflags-y += -DDISABLE_BRANCH_PROFILING
 ccflags-y += -fno-builtin
@@ -32,10 +24,6 @@ ifneq ($(c-gettimeofday-y),)
   CFLAGS_vgettimeofday.o += -fPIC -include $(c-gettimeofday-y)
 endif
 
-ifneq ($(c-getrandom-y),)
-  CFLAGS_getrandom.o += -fPIC -include $(c-getrandom-y)
-endif
-
 CFLAGS_hwprobe.o += -fPIC
 
 # Build rules

arch/riscv/kernel/vdso/Makefile

@@ -80,7 +80,6 @@ VERSION
 #ifndef COMPAT_VDSO
 		__vdso_riscv_hwprobe;
 #endif
-		__vdso_getrandom;
 	local: *;
 	};
 }

arch/riscv/kernel/vdso/getrandom.c

@@ -11,8 +11,6 @@
 #include "../../../../arch/loongarch/vdso/vgetrandom-chacha.S"
 #elif defined(__powerpc__) || defined(__powerpc64__)
 #include "../../../../arch/powerpc/kernel/vdso/vgetrandom-chacha.S"
-#elif defined(__riscv) && __riscv_xlen == 64
-#include "../../../../arch/riscv/kernel/vdso/vgetrandom-chacha.S"
 #elif defined(__s390x__)
 #include "../../../../arch/s390/kernel/vdso64/vgetrandom-chacha.S"
 #elif defined(__x86_64__)