[Bug ld/30141] New: LD does not mark INIT section as IMAGE_SCN_MEM_DISCARDABLE

[pali at kernel dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30141

            Bug ID: 30141
           Summary: LD does not mark INIT section as
                    IMAGE_SCN_MEM_DISCARDABLE
           Product: binutils
           Version: 2.39
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: ld
          Assignee: unassigned at sourceware dot org
          Reporter: pali at kernel dot org
  Target Milestone: ---

INIT code section is used in NT drivers (Native PE binaries) only during
initilization and section should be marked as discardable to not waste memory.

LD does not mark this section as discardable.

Test case: Very simple NT kernel driver with entry point which does nothing:

$ cat test-init.c
__attribute__((stdcall))
long DriverEntry(void *DriverObject, void *RegistryPath) asm("DriverEntry")
__attribute__((section("INIT")));

__attribute__((stdcall))
long DriverEntry(void *DriverObject, void *RegistryPath) {
        return 0;
}

$ x86_64-w64-mingw32-gcc -nostartfiles -nodefaultlibs -nostdlib
-Wl,--subsystem,native -e DriverEntry test-init.c -o test-init.sys

$ readpe test-init.sys | grep -A 11 'Name:\s*INIT'
export directory not found
        Name:                            INIT
        Virtual Address:                 0x2000
        Physical Address:                0x14
        Size:                            0x200 (512 bytes)
        Pointer To Data:                 0x600
        Relocations:                     0
        Characteristics:                 0x60300020
        Characteristic Names
                                             IMAGE_SCN_CNT_CODE
                                             IMAGE_SCN_MEM_EXECUTE
                                             IMAGE_SCN_MEM_READ
    Section


As can be seen in readpe output, INIT section is not marked as discardable
(IMAGE_SCN_MEM_DISCARDABLE). I'm not sure how to verify this with objdump as I
do not know how it shows IMAGE_SCN_* flags. So I used readpe for verification.

For NT kernel drivers same applies for .idata and .rsrc sections which should
be discardable too.

-- 
You are receiving this mail because:
You are on the CC list for the bug.