From d7f679ec868e8675c269c742a2ba58c6aceaf52b Mon Sep 17 00:00:00 2001
From: Heiko Carstens <hca@linux.ibm.com>
Date: Fri, 1 Dec 2023 15:42:16 +0100
Subject: [PATCH] s390/fpu: remove ARCH_WANTS_DYNAMIC_TASK_STRUCT support
s390 selects ARCH_WANTS_DYNAMIC_TASK_STRUCT in order to make the size of
the task structure dependent on the availability of the vector
facility. This doesn't make sense anymore because since many years all
machines provide the vector facility.
Therefore simplify the code a bit and remove s390 support for
ARCH_WANTS_DYNAMIC_TASK_STRUCT.
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
---
arch/s390/Kconfig | 1 -
arch/s390/include/asm/processor.h | 6 +-----
arch/s390/kernel/process.c | 2 +-
arch/s390/kernel/setup.c | 17 -----------------
4 files changed, 2 insertions(+), 24 deletions(-)
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 3bec98d20283b..b5dbac684bbd5 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -123,7 +123,6 @@ config S390
select ARCH_USE_BUILTIN_BSWAP
select ARCH_USE_CMPXCHG_LOCKREF
select ARCH_USE_SYM_ANNOTATIONS
- select ARCH_WANTS_DYNAMIC_TASK_STRUCT
select ARCH_WANTS_NO_INSTR
select ARCH_WANT_DEFAULT_BPF_JIT
select ARCH_WANT_IPC_PARSE_VERSION
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 0b625373a255e..92146d63c25e9 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -184,11 +184,7 @@ struct thread_struct {
struct gs_cb *gs_cb; /* Current guarded storage cb */
struct gs_cb *gs_bc_cb; /* Broadcast guarded storage cb */
struct pgm_tdb trap_tdb; /* Transaction abort diagnose block */
- /*
- * Warning: 'fpu' is dynamically-sized. It *MUST* be at
- * the end.
- */
- struct fpu fpu; /* FP and VX register save area */
+ struct fpu fpu; /* FP and VX register save area */
};
/* Flag to disable transactions. */
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 2580004177248..4e3b366589fb6 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -89,7 +89,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
*/
save_fpu_regs();
- memcpy(dst, src, arch_task_struct_size);
+ *dst = *src;
dst->thread.fpu.regs = dst->thread.fpu.fprs;
/*
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index c0e7cfdd77476..d1f3b56e7afc2 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -819,22 +819,6 @@ static void __init setup_randomness(void)
static_branch_enable(&s390_arch_random_available);
}
-/*
- * Find the correct size for the task_struct. This depends on
- * the size of the struct fpu at the end of the thread_struct
- * which is embedded in the task_struct.
- */
-static void __init setup_task_size(void)
-{
- int task_size = sizeof(struct task_struct);
-
- if (!MACHINE_HAS_VX) {
- task_size -= sizeof(__vector128) * __NUM_VXRS;
- task_size += sizeof(freg_t) * __NUM_FPRS;
- }
- arch_task_struct_size = task_size;
-}
-
/*
* Issue diagnose 318 to set the control program name and
* version codes.
@@ -927,7 +911,6 @@ void __init setup_arch(char **cmdline_p)
os_info_init();
setup_ipl();
- setup_task_size();
setup_control_program_code();
/* Do some memory reservations *before* memory is added to memblock */
--
2.30.2