Hey, On Sun, 23 Nov 2025 16:09:41 +0100 (CET), René Rebe <[email protected]> wrote:
> On Sun, 23 Nov 2025 15:57:24 +0100, "Christophe Leroy (CS GROUP)" > <[email protected]> wrote: > > > Le 23/11/2025 à 13:13, René Rebe a écrit : > > > Building a size optimized ppc64 kernel (-Os), gcc emits more FP > > > save/restore symbols, that the linker generates on demand into the > > > .sfpr section. Explicitly allow-list those in scripts/mod/modpost.c, > > > too. They are needed for the amdgpu in-kernel floating point support. > > > > Would have been interested to know with which version of GCC the > > problem started. > > idk, maybe forever, or at least a decade fo GCC? Most devs probably > don't build size optimized, and addtionally we only use in kernel > floating point for amdgpu since recently? Should I add Fixes: for the > in-kernel FP hash? > > > By the way you seem to fix the problem for modules, but does it also > > work when amdgpu is in kernel ? I would have expected a need to add > > functions in arch/powerpc/lib/crtsavres.S as well, just like following > > commits: > > > > 8fe9c93e7453 ("powerpc: Add vr save/restore functions") > > 7fca5dc8aa7a ("powerpc: Fix module building for gcc 4.5 and 64 bit") > > da3de6df33f5 ("[POWERPC] Fix -Os kernel builds with newer gcc > > versions") > > idk, I avoid linking that big stuff directly into the kernel and would > need to specically test that, too. I guess I go do that now, too, ... It appears built-in amdgpu FP somehow magically works for me: debug-linux:[linux-6.17]# grep DRM.*AMD .config CONFIG_DRM_AMDGPU=y CONFIG_DRM_AMDGPU_SI=y CONFIG_DRM_AMDGPU_CIK=y CONFIG_DRM_AMDGPU_USERPTR=y CONFIG_DRM_AMD_ACP=y CONFIG_DRM_AMD_DC=y CONFIG_DRM_AMD_DC_FP=y CONFIG_DRM_AMD_DC_SI=y ... CC drivers/gpu/drm/amd/amdgpu/../display/modules/hdcp/hdcp_ddc.o CC drivers/gpu/drm/amd/amdgpu/../display/modules/hdcp/hdcp_log.o CC drivers/gpu/drm/amd/amdgpu/../display/modules/hdcp/hdcp_psp.o CC drivers/gpu/drm/amd/amdgpu/../display/modules/hdcp/hdcp.o CC drivers/gpu/drm/amd/amdgpu/../display/modules/hdcp/hdcp1_execution.o CC drivers/gpu/drm/amd/amdgpu/../display/modules/hdcp/hdcp1_transition.o CC drivers/gpu/drm/amd/amdgpu/../display/modules/hdcp/hdcp2_execution.o CC drivers/gpu/drm/amd/amdgpu/../display/modules/hdcp/hdcp2_transition.o AR drivers/gpu/drm/amd/amdgpu/built-in.a AR drivers/gpu/drm/built-in.a AR drivers/gpu/built-in.a AR drivers/built-in.a AR built-in.a AR vmlinux.a LD vmlinux.o GEN modules.builtin.modinfo GEN modules.builtin MODPOST vmlinux.symvers CC .vmlinux.export.o UPD include/generated/utsversion.h CC init/version-timestamp.o KSYMS .tmp_vmlinux0.kallsyms.S AS .tmp_vmlinux0.kallsyms.o LD .tmp_vmlinux1 NM .tmp_vmlinux1.syms KSYMS .tmp_vmlinux1.kallsyms.S AS .tmp_vmlinux1.kallsyms.o LD .tmp_vmlinux2 NM .tmp_vmlinux2.syms KSYMS .tmp_vmlinux2.kallsyms.S AS .tmp_vmlinux2.kallsyms.o LD vmlinux.unstripped NM System.map SORTTAB vmlinux.unstripped make[3]: Nothing to be done for 'vmlinux.unstripped'. OBJCOPY vmlinux So I guess the patch is good to go after clarifying which kind of Fixes: to use? Thanks! René > > > MODPOST Module.symvers > > > ERROR: modpost: "_restfpr_20" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] > > > undefined! > > > ERROR: modpost: "_restfpr_26" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] > > > undefined! > > > ERROR: modpost: "_restfpr_22" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] > > > undefined! > > > ERROR: modpost: "_savegpr1_27" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] > > > undefined! > > > ERROR: modpost: "_savegpr1_25" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] > > > undefined! > > > ERROR: modpost: "_restfpr_28" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] > > > undefined! > > > ERROR: modpost: "_savegpr1_29" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] > > > undefined! > > > ERROR: modpost: "_savefpr_20" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] > > > undefined! > > > ERROR: modpost: "_savefpr_22" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] > > > undefined! > > > ERROR: modpost: "_restfpr_15" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] > > > undefined! > > > WARNING: modpost: suppressed 56 unresolved symbol warnings because > > > there were too many) > > > Signed-off-by: René Rebe <[email protected]> > > > --- > > > V2: description > > > Theoretically for -stable, but no previous commit that broke it. > > > > In that case you have to add Cc: [email protected] > > Add indeed it is likely a gcc upgrade that broke it, not a previous > > commit. > > Should I then simply use enabling amdgpu dc_fp and in-kernel FP as the > breaking commit for Fixes:? > > Thanks! > > René > > > > --- > > > scripts/mod/modpost.c | 4 ++++ > > > 1 file changed, 4 insertions(+) > > > diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c > > > index 47c8aa2a6939..133dfa16308a 100644 > > > --- a/scripts/mod/modpost.c > > > +++ b/scripts/mod/modpost.c > > > @@ -602,6 +602,10 @@ static int ignore_undef_symbol(struct elf_info > > > *info, const char *symname) > > > /* Special register function linked on all modules > > > during final link of > > > .ko */ > > > if (strstarts(symname, "_restgpr0_") || > > > strstarts(symname, "_savegpr0_") || > > > + strstarts(symname, "_restgpr1_") || > > > + strstarts(symname, "_savegpr1_") || > > > + strstarts(symname, "_restfpr_") || > > > + strstarts(symname, "_savefpr_") || > > > strstarts(symname, "_restvr_") || > > > strstarts(symname, "_savevr_") || > > > strcmp(symname, ".TOC.") == 0) > > > > -- > René Rebe, ExactCODE GmbH, Berlin, Germany > https://exactco.de • https://t2linux.com • https://patreon.com/renerebe -- René Rebe, ExactCODE GmbH, Berlin, Germany https://exactco.de • https://t2linux.com • https://patreon.com/renerebe
