[PATCH 2/3] um: Remove highmem leftovers

From: Tiwei Bie
Date: Fri Sep 13 2024 - 10:22:24 EST


Highmem was only supported on UML/i386. And the support has been
removed by commit a98a6d864d3b ("um: Remove broken highmem support").
Remove the leftovers and stop UML from trying to setup highmem when
the sum of physmem_size and iomem_size exceeds max_physmem.

Signed-off-by: Tiwei Bie <tiwei.btw@xxxxxxxxxxxx>
---
arch/um/drivers/virtio_uml.c | 9 +--------
arch/um/include/shared/as-layout.h | 1 -
arch/um/include/shared/mem_user.h | 5 ++---
arch/um/kernel/mem.c | 3 ---
arch/um/kernel/physmem.c | 30 +++++++++++-------------------
arch/um/kernel/um_arch.c | 17 +++++++----------
6 files changed, 21 insertions(+), 44 deletions(-)

diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c
index 2b6e701776b6..e7f5556e3c96 100644
--- a/arch/um/drivers/virtio_uml.c
+++ b/arch/um/drivers/virtio_uml.c
@@ -72,7 +72,7 @@ struct virtio_uml_vq_info {
bool suspended;
};

-extern unsigned long long physmem_size, highmem;
+extern unsigned long long physmem_size;

#define vu_err(vu_dev, ...) dev_err(&(vu_dev)->pdev->dev, ##__VA_ARGS__)

@@ -673,13 +673,6 @@ static int vhost_user_set_mem_table(struct virtio_uml_device *vu_dev)

if (rc < 0)
return rc;
- if (highmem) {
- msg.payload.mem_regions.num++;
- rc = vhost_user_init_mem_region(__pa(end_iomem), highmem,
- &fds[1], &msg.payload.mem_regions.regions[1]);
- if (rc < 0)
- return rc;
- }

return vhost_user_send(vu_dev, false, &msg, fds,
msg.payload.mem_regions.num);
diff --git a/arch/um/include/shared/as-layout.h b/arch/um/include/shared/as-layout.h
index 06292fca5a4d..61965a06c18a 100644
--- a/arch/um/include/shared/as-layout.h
+++ b/arch/um/include/shared/as-layout.h
@@ -41,7 +41,6 @@ extern unsigned long uml_physmem;
extern unsigned long uml_reserved;
extern unsigned long end_vm;
extern unsigned long start_vm;
-extern unsigned long long highmem;

extern unsigned long brk_start;

diff --git a/arch/um/include/shared/mem_user.h b/arch/um/include/shared/mem_user.h
index 11a723a58545..adfa08062f88 100644
--- a/arch/um/include/shared/mem_user.h
+++ b/arch/um/include/shared/mem_user.h
@@ -47,10 +47,9 @@ extern int iomem_size;
#define ROUND_4M(n) ((((unsigned long) (n)) + (1 << 22)) & ~((1 << 22) - 1))

extern unsigned long find_iomem(char *driver, unsigned long *len_out);
-extern void mem_total_pages(unsigned long physmem, unsigned long iomem,
- unsigned long highmem);
+extern void mem_total_pages(unsigned long physmem, unsigned long iomem);
extern void setup_physmem(unsigned long start, unsigned long usable,
- unsigned long len, unsigned long long highmem);
+ unsigned long len);
extern void map_memory(unsigned long virt, unsigned long phys,
unsigned long len, int r, int w, int x);

diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index a5b4fe2ad931..5026668dc054 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -6,7 +6,6 @@
#include <linux/stddef.h>
#include <linux/module.h>
#include <linux/memblock.h>
-#include <linux/highmem.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/slab.h>
@@ -51,8 +50,6 @@ EXPORT_SYMBOL(empty_zero_page);
pgd_t swapper_pg_dir[PTRS_PER_PGD];

/* Initialized at boot time, and readonly after that */
-unsigned long long highmem;
-EXPORT_SYMBOL(highmem);
int kmalloc_ok = 0;

/* Used during early boot */
diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c
index fb2adfb49945..cc5238c1bf1e 100644
--- a/arch/um/kernel/physmem.c
+++ b/arch/um/kernel/physmem.c
@@ -24,17 +24,14 @@ EXPORT_SYMBOL(high_physmem);

extern unsigned long long physmem_size;

-void __init mem_total_pages(unsigned long physmem, unsigned long iomem,
- unsigned long highmem)
+void __init mem_total_pages(unsigned long physmem, unsigned long iomem)
{
- unsigned long phys_pages, highmem_pages;
- unsigned long iomem_pages, total_pages;
+ unsigned long phys_pages, iomem_pages, total_pages;

- phys_pages = physmem >> PAGE_SHIFT;
- iomem_pages = iomem >> PAGE_SHIFT;
- highmem_pages = highmem >> PAGE_SHIFT;
+ phys_pages = physmem >> PAGE_SHIFT;
+ iomem_pages = iomem >> PAGE_SHIFT;

- total_pages = phys_pages + iomem_pages + highmem_pages;
+ total_pages = phys_pages + iomem_pages;

max_mapnr = total_pages;
}
@@ -64,13 +61,12 @@ void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
* @reserve_end: end address of the physical kernel memory.
* @len: Length of total physical memory that should be mapped/made
* available, in bytes.
- * @highmem: Number of highmem bytes that should be mapped/made available.
*
- * Creates an unlinked temporary file of size (len + highmem) and memory maps
+ * Creates an unlinked temporary file of size (len) and memory maps
* it on the last executable image address (uml_reserved).
*
* The offset is needed as the length of the total physical memory
- * (len + highmem) includes the size of the memory used be the executable image,
+ * (len) includes the size of the memory used be the executable image,
* but the mapped-to address is the last address of the executable image
* (uml_reserved == end address of executable image).
*
@@ -78,19 +74,19 @@ void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
* of all user space processes/kernel tasks.
*/
void __init setup_physmem(unsigned long start, unsigned long reserve_end,
- unsigned long len, unsigned long long highmem)
+ unsigned long len)
{
unsigned long reserve = reserve_end - start;
long map_size = len - reserve;
int err;

- if(map_size <= 0) {
+ if (map_size <= 0) {
os_warn("Too few physical memory! Needed=%lu, given=%lu\n",
reserve, len);
exit(1);
}

- physmem_fd = create_mem_file(len + highmem);
+ physmem_fd = create_mem_file(len);

err = os_map_memory((void *) reserve_end, physmem_fd, reserve,
map_size, 1, 1, 1);
@@ -109,7 +105,7 @@ void __init setup_physmem(unsigned long start, unsigned long reserve_end,
os_write_file(physmem_fd, __syscall_stub_start, PAGE_SIZE);
os_fsync_file(physmem_fd);

- memblock_add(__pa(start), len + highmem);
+ memblock_add(__pa(start), len);
memblock_reserve(__pa(start), reserve);

min_low_pfn = PFN_UP(__pa(reserve_end));
@@ -137,10 +133,6 @@ int phys_mapping(unsigned long phys, unsigned long long *offset_out)
region = region->next;
}
}
- else if (phys < __pa(end_iomem) + highmem) {
- fd = physmem_fd;
- *offset_out = phys - iomem_size;
- }

return fd;
}
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 8e594cda6d77..8f86aa468b50 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -366,18 +366,15 @@ int __init linux_main(int argc, char **argv)

setup_machinename(init_utsname()->machine);

- highmem = 0;
+ physmem_size = (physmem_size + PAGE_SIZE - 1) & PAGE_MASK;
iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
+
max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC;

- /*
- * Zones have to begin on a 1 << MAX_PAGE_ORDER page boundary,
- * so this makes sure that's true for highmem
- */
- max_physmem &= ~((1 << (PAGE_SHIFT + MAX_PAGE_ORDER)) - 1);
if (physmem_size + iomem_size > max_physmem) {
- highmem = physmem_size + iomem_size - max_physmem;
- physmem_size -= highmem;
+ physmem_size = max_physmem - iomem_size;
+ os_info("Physical memory size shrunk to %llu bytes\n",
+ physmem_size);
}

high_physmem = uml_physmem + physmem_size;
@@ -413,8 +410,8 @@ void __init setup_arch(char **cmdline_p)
u8 rng_seed[32];

stack_protections((unsigned long) &init_thread_info);
- setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
- mem_total_pages(physmem_size, iomem_size, highmem);
+ setup_physmem(uml_physmem, uml_reserved, physmem_size);
+ mem_total_pages(physmem_size, iomem_size);
uml_dtb_init();
read_initrd();

--
2.34.1