On Tue, 7 Jan 2020 at 19:08, Arvind Sankar <nivedita@xxxxxxxxxxxx> wrote: > > On Tue, Jan 07, 2020 at 06:59:57PM +0100, Ard Biesheuvel wrote: > > On Tue, 7 Jan 2020 at 18:58, Arvind Sankar <nivedita@xxxxxxxxxxxx> wrote: > > > > > > On Tue, Jan 07, 2020 at 03:28:31PM +0100, Ard Biesheuvel wrote: > > > > > > > > Unfortunately, the command line option implements a weaker form of > > > > visibility than the pragma, so it probably comes down to setting the > > > > pragma in a .h file that gets -include'd via the command line so it is > > > > guaranteed to be seen first. > > > > > > Tried hacking that in and it works, tested with gcc 4.6.4. > > > > Excellent. But in my testing locally, I don't get any GOT entries in > > the first place, strangely enough. So what changes in the output for > > you with visibility hidden compared to before? > > Works with 32-bit as well. > > Are you checking libstub or boot/compressed? Below is with gcc 4.6 (but > latest binutils). With gcc 9, there's only one left -- trampoline_32bit_src > in pgtable_64. > I am looking at the size of the .got section in boot/compressed/vmlinux, and it is 0x0 on 64-bit, and 0xc (i.e., only the .got.plt fixup code) on 32-bit. Could you please check whether passing -Bsymbolic to the linker gives the same result btw? > acpi.o > 000000000000025b R_X86_64_REX_GOTPCRELX boot_params-0x0000000000000004 > cmdline.o > 00000000000001d3 R_X86_64_REX_GOTPCRELX boot_params-0x0000000000000004 > 00000000000001f3 R_X86_64_REX_GOTPCRELX boot_params-0x0000000000000004 > 0000000000000223 R_X86_64_REX_GOTPCRELX boot_params-0x0000000000000004 > cpuflags.o > 00000000000000a3 R_X86_64_REX_GOTPCRELX cpu_vendor-0x0000000000000004 > 00000000000000c5 R_X86_64_REX_GOTPCRELX cpu-0x0000000000000004 > 0000000000000127 R_X86_64_REX_GOTPCRELX cpu-0x0000000000000004 > 0000000000000144 R_X86_64_REX_GOTPCRELX cpu-0x0000000000000004 > 0000000000000153 R_X86_64_REX_GOTPCRELX cpu-0x0000000000000004 > 000000000000017b R_X86_64_REX_GOTPCRELX cpu-0x0000000000000004 > early_serial_console.o > 000000000000005a R_X86_64_REX_GOTPCRELX early_serial_base-0x0000000000000004 > 0000000000000165 R_X86_64_REX_GOTPCRELX early_serial_base-0x0000000000000004 > eboot.o > efi_thunk_64.o > error.o > head_64.o > kaslr_64.o > 00000000000001e7 R_X86_64_REX_GOTPCRELX ptrs_per_p4d-0x0000000000000004 > 0000000000000372 R_X86_64_REX_GOTPCRELX __default_kernel_pte_mask-0x0000000000000004 > 000000000000038b R_X86_64_REX_GOTPCRELX pgdir_shift-0x0000000000000004 > 00000000000003ac R_X86_64_REX_GOTPCRELX __pgtable_l5_enabled-0x0000000000000004 > 000000000000040a R_X86_64_REX_GOTPCRELX __pgtable_l5_enabled-0x0000000000000004 > 00000000000004db R_X86_64_REX_GOTPCRELX __force_order-0x0000000000000004 > 00000000000004f2 R_X86_64_REX_GOTPCRELX __pgtable_l5_enabled-0x0000000000000004 > 0000000000000517 R_X86_64_REX_GOTPCRELX _pgtable-0x0000000000000004 > 00000000000005f3 R_X86_64_REX_GOTPCRELX __force_order-0x0000000000000004 > kaslr.o > 0000000000000281 R_X86_64_REX_GOTPCRELX boot_params-0x0000000000000004 > 00000000000003e3 R_X86_64_REX_GOTPCRELX boot_params-0x0000000000000004 > 0000000000000ba1 R_X86_64_REX_GOTPCRELX __force_order-0x0000000000000004 > 0000000000000bb4 R_X86_64_REX_GOTPCRELX boot_params-0x0000000000000004 > 0000000000000cc8 R_X86_64_REX_GOTPCRELX free_mem_ptr-0x0000000000000004 > 0000000000000cd2 R_X86_64_REX_GOTPCRELX free_mem_end_ptr-0x0000000000000004 > 0000000000000d6e R_X86_64_REX_GOTPCRELX free_mem_ptr-0x0000000000000004 > 0000000000000f63 R_X86_64_REX_GOTPCRELX __pgtable_l5_enabled-0x0000000000000004 > kernel_info.o > mem_encrypt.o > misc.o > 0000000000000015 R_X86_64_REX_GOTPCRELX free_mem_ptr-0x0000000000000004 > 000000000000001f R_X86_64_REX_GOTPCRELX free_mem_end_ptr-0x0000000000000004 > 0000000000002965 R_X86_64_REX_GOTPCRELX early_serial_base-0x0000000000000004 > 0000000000002a43 R_X86_64_REX_GOTPCRELX boot_params-0x0000000000000004 > 0000000000002b8e R_X86_64_REX_GOTPCRELX boot_params-0x0000000000000004 > 0000000000002bec R_X86_64_REX_GOTPCRELX boot_params-0x0000000000000004 > 0000000000002c10 R_X86_64_REX_GOTPCRELX free_mem_end_ptr-0x0000000000000004 > 0000000000002c17 R_X86_64_REX_GOTPCRELX free_mem_ptr-0x0000000000000004 > 0000000000002d16 R_X86_64_REX_GOTPCRELX trampoline_32bit-0x0000000000000004 > 0000000000002f97 R_X86_64_REX_GOTPCRELX boot_params-0x0000000000000004 > 0000000000002fea R_X86_64_REX_GOTPCRELX boot_params-0x0000000000000004 > pgtable_64.o > 000000000000000d R_X86_64_REX_GOTPCRELX boot_params-0x0000000000000004 > 000000000000010a R_X86_64_REX_GOTPCRELX trampoline_32bit_src-0x0000000000000004 > 0000000000000191 R_X86_64_REX_GOTPCRELX __force_order-0x0000000000000004 > 0000000000000376 R_X86_64_REX_GOTPCRELX __force_order-0x0000000000000004 > piggy.o > string.o
